Harry lay awake in bed while Tom got dressed. Harry could see his silhouette, outlined against the window in the pre-dawn light, as he buttoned up his shirt and tucked it into his trousers.

They'd tried the Room of Requirement last night. However, no sooner had they entered the seventh-floor corridor than they encountered the little blonde girl whose appearance Tom had taken just an hour before. She watched them rather stupidly as they passed the stretch of stone wall that disguised the entrance to the Room, her fingers flexing on the heavy cauldron she was cradling against her chest.

Harry and Tom had agreed together, in a quiet moment before the others got back from class, that they would go before breakfast the next morning. Harry regretted that promise now. His bed was warm, and he could still feel the imprint in the mattress where Tom had lain. Harry rubbed his face against the pillow, wondering if Tom would be willing to call it off—to go later, or even on another day. What was so urgent about a Horcrux anyway that it couldn't wait until Harry was fully awake? Crabbe and Nott and Goyle had been searching for almost two months now and hadn't found it—it would be fine to leave it, surely.

Tom nudged Harry's shoulder. Harry burrowed deeper under the covers in response, which only made Tom laugh quietly.

"Come on," he whispered, sitting down on the bed behind him and combing his fingers through Harry's hair. "Get up, Harry, before I conjure some water to pour on your head."

Sadist, Harry thought, but he flipped down the covers all the same.

They slipped out of the dormitory a few minutes later, knowing that the heavy curtains on the rest of the beds would muffle the noise of their departure. If anyone did hear, they would assume Harry and Tom were going to the showers downstairs.

"We might not find it on the first try," Tom said, as they cleared the portrait hole and began walking down the corridor to the intersection. The Invisibility cloak was stowed down Harry's shirt—it was too early for Filch to be awake. "We might have to keep going back."

Harry suppressed a yawn. He was walking a few feet behind Tom, occasionally glancing out of the windows. The brightest stars were still out, but the horizon was visible in the east. In an hour or so it would be dawn. He glanced back at Tom and noticed for the first time that Harry's own red rucksack was slung over his shoulder.

"What's that for?"

"Hmm?" Tom asked, turning back to see what he was looking at. Unlike Harry, he seemed wide-awake, filled with certainty and purpose. "Oh! It's for the Horcrux, if we find it."

Harry frowned. Something about that struck him as odd. "How big do you think it's going to be?"

"No idea, but I expect it will be something impressive."

"Why?" Harry asked, thinking of the old Muggle diary and the ugly ring.

Tom obviously thought this question—or perhaps the expression on Harry's face—was too stupid or insulting to deserve an answer, because he hitched the rucksack higher on his shoulder and picked up the pace.

There were no little girls waiting outside the Room of Requirement. Tom strode up and down in front of the wall until it resolved itself into a door, then opened it with a flourish.

"Welcome to the Room of Hidden Things," he said grandly.

It was like a great cathedral, a huge stone room with darkened windows set into an arching stone vault. Hundreds of floating balls of light hovered in the air, casting a warm, dim glow that reminded Harry of sconces in a library.

The fog of sleep lifted as Harry stepped inside. The space around the door was raised over the rest of the room like a diving board over a huge swimming pool. Below sprawled a maze of broken furniture, towering stacks of old books, rolled-up rugs and tapestries, suits of armour missing heads and gauntlets. Here and there was a flash of motion: books rearranging themselves, a golden harp leaping from shelf to shelf, and even, to Harry's amazement, a few of the winged keys that had once lived in tunnel leading to the Mirror of Erised. Flitwick's magic had begun to wear off, and their wings fluttered feebly as they glided low over the stacks.

Tom looked smug at his reaction. "Let's go this way," he said, leading Harry down the rickety wooden staircase and into the maze itself. "I'm not sure where it is, so we'll have to search the whole thing until I feel something."

Down at ground level, it was like a city. Wide streets led to smaller alleyways, which in turn led to nooks and crannies too small for anyone but a house-elf to fit into. Harry hurried behind Tom, head twisting from side to side. Most of the stuff was rubbish, he realised, although punctuated by spots of colour, like the brilliant red of a portrait, a golden birdcage, a line of jewel-green bottles on a high shelf. Harry leapt out of the way as something brown and furry leapt from beneath a shattered display cabinet—a moment later he realised it was a feral copy of The Monster Book of Monsters.

"Who puts these things here?"

"I don't know for certain," Tom replied. "House-elves use it—I occasionally used to see them in here. And I think Hogwarts itself uses it too, when it changes its layout. And other students, I suppose, hiding contraband, although I think very few know of it."

"How did you find it?"

"Remember when I told you that it took me three years to find the entrance to the Chamber of Secrets? I found plenty of other things while I was looking, like the passages out of the school, and this place—although I had no idea that you could turn the Room into other things. I stumbled across it in third year when I was trying to get rid of a dead owl, and I've been coming here ever since." Tom smiled at a fond memory. "I used to look for valuable things during Christmas and Easter break when everyone else had gone home for the holiday. When I found something really good, I'd take it to Burke to earn some money for the summer."

"Burke?"

"Caractacus Burke—he runs an antiques shop in Knockturn Alley."

Harry could just imagine that, he thought, as he watched Tom examine a Fanged Frisbee twitching on a nearby shelf. Little fourth-year Tom in his too-short school robes, haggling with a shopkeeper over something he'd stolen. Elbows on the counter, dimples, oh won't you give me another three Sickles for it, sir?

The atmosphere grew more secretive as they went further in; the passages narrowed, and often closed in overhead with a web of books, curtains and bedcovers. It felt as if the objects they passed had been lying here for a long time, and were content not to be seen by human eyes again. Harry had a sense of being in a space that was not for him, that belonged to the castle itself. Every now and again they heard a distant rumble, which Tom said was caused by the stacks rearranging themselves.

It was hard to keep track of their direction, so a few times Harry (who was a better climber than Tom) scrambled to the top of a pile of furniture and pointed out the door. Gradually, the sky outside began to lighten. Light shone from the high windows in the loft, piercing through the gloom like spears, catching dust motes dancing in the air. One by one, the floating lamps winked out.

"We can miss breakfast," Tom said, noticing Harry's agitation. "It's Saturday anyway."

"Ron and Hermione will notice."

"So?"

Tom's head was cocked to the side, as if he was listening for a sound no one else could hear. It was a bit like taking your dog for a walk, Harry thought, trying not to laugh.

"You really don't like my friends, do you?"

"Did you expect me to?"

"Not really," Harry said. "I don't think you like anyone in this time, not Seamus or Mrs Weasley or even Slughorn."

"I do like Slughorn," Tom said. "And I like you."

Harry sat down on a dusty velvet pouffe as Tom poked his head into a fissure between two precariously-stacked piles of stone.

"Why?" he asked.

"He's a competent teacher and I admire his pragmatic attitude."

"No, why do you like me?"

Tom took head out of the fissure. There was a puzzled expression on his face as he looked at Harry.

"I don't know," he said. "I suppose I've just gotten used to having you around. You're like a pet at this point."

"Thanks."

"Plus you're really easy."

Harry shot up from the pouffe. "I am not!"

"I kidnapped you and we were having sex within a week."

"It wasn't that fast!" Harry protested, although now he thought about it, perhaps it was.

Actually, it might have been less than a week.

"I distinctly remember you being involved too," he said heatedly, now following Tom as he headed down another, wider passageway. "And you weren't exactly hard to get into bed either. If I'm easy, what does that make you?"

Tom chuckled, and it suddenly dawned on Harry that Tom had successfully steered the conversation away from Ron and Hermione.

"Are you trying to change the topic?"

"What topic?"

"You are!" Harry leapt in front of Tom, blocking his path. "You don't want to talk about my friends? No . . . actually, have you been trying to isolate me from them?"

"I don't know what you mean," Tom said.

"These last few weeks," Harry said, mind working furiously. "You've been trying to drive a wedge between me and Hermione. I thought it was just because you didn't want her to stop us from trailing Malfoy, but it's more than that, isn't it? You're threatened by them."

"Don't be insulting," Tom snapped. "Granger can hardly pull her frizzy head from a book for long enough to eat and sleep, and don't even get me started on Weasley. I don't know what you see in them."

Privately, Harry thought that Tom might be surprised if he was ever in a duel with Ron or Hermione—or better, both of them together, but he wasn't going to tell him that.

"I don't mean physically threatened," he said. "I know you don't think that anyone could ever match up to your incredible magical prowess. I meant you're worried that one day I'll choose them over you."

Tom had come to a halt. His hands were shoved deep into his pockets and there was a scowl on his startlingly pretty face. He didn't say anything.

"Or is it possessiveness?" Harry asked. "Is that it? I know you don't like it when I talk to other people. If it is, that's pretty fucking hypocritical."

"How so?"

"Don't think I haven't seen you flirting with people," Harry said, thinking of Tom's tendency to sit next to pretty girls. The way, two weeks ago, he had plucked a leaf out of Ginny's hair at dinner (although, to be fair, that might just have been to upset Ron). "I know you cheated on Abraxas. You're not the one who should be feeling insecure here."

"I wasn't together with Abraxas," Tom said. "He was just convenient." He shoved past Harry and kept going, ducking under the objects that protruded from the walls of the passageway. Harry followed, thinking about what he had said. I wasn't together with Abraxas. As if he and Harry were together.

"You wouldn't like it if I flirted with someone else," Harry said to his back. In fact, he should try that sometime, just to see the look on Tom's face.

"I don't know what you're complaining for," Tom shot back. "I can tell you're happy."

Was he? Harry wondered, a little thrown by the idea. He wasn't particularly in the habit of considering his own happiness. But now Tom had mentioned it, Harry realised he was right: on some level Harry was happy this year. He enjoyed the constant company and excitement and companionship, and he felt warm every time he thought of his adoption by Sirius, the fact that he had a guardian now, one who liked and cared about him. In fact, there was a new, definite sense of belonging—for once, Harry knew who he was going to spend Christmas with without even having to ask.

"I suppose there are some things I like," Harry said diffidently. "I don't enjoy you pushing me around though, or how patronising you can be."

"You'd probably be really bored if I wasn't here," Tom sneered.

"That's what I mean by patronising! I did just fine before you turned up."

Tom paused, and Harry saw that they had reached a bottleneck in the passage. A curving stone wall lay on one side; the other was made up of shelves bearing little parcels of what looked like bark, all stacked up and tied with string, as if they were important. Harry plucked one off the shelf, but he couldn't see any markings on it. It crumbled away to dirt in his fingers.

Then Tom moved aside, and they spilled out into an open space, bright after the dimness of the passageway. Harry squinted against the light—it must have been eight or nine o'clock by now, he thought. The space was a bit like a clearing in a forest, with high walls made of rubbish. He could see a pile of desks, a stained glass window with several panes missing, a trunk full of dented iron plates, and, incongruously, what looked like a Muggle postbox.

"Do you wish I hadn't taken you?" Tom asked.

"Do I wish you hadn't murdered Pansy?" Harry asked. "Yes, of course I do."

"No," Tom said, and there was a strange intensity to his voice. "Forget Pansy for a minute. Do you wish I hadn't taken you?"

A barrier formed in Harry's throat. How was he supposed to answer that? So many people would still be alive if Tom hadn't woken up in his diary; Pansy, Dudley, that nameless Death Eater Tom had suffocated in the Ministry. Harry still hadn't processed all the death—he'd stuffed the idea of it behind a door in his mind, a door that never opened, but sometimes creaked in the middle of the night, when he woke up and couldn't get back to sleep. It baffled him that Tom couldn't understand how he felt about it—it was like there was a cold, dark place inside him that Harry was never able to reach. Something extra he was carrying around with him.

Or maybe not something extra. Maybe it was something Tom was missing, that everyone else had.

"Yes," Harry said, when the silence stretched. "Of course I wish that."

Tom took a step forward, and Harry took a reflexive step back. The wall was behind him though, and Tom closed the distance and put his hands on Harry's hips. Harry grabbed his wrists to stop them going further.

"Really?" Tom said. "You don't miss living with me at the cottage at all?"

"I suppose I miss the simplicity of it," Harry admitted. "And not having to do homework."

"Nothing else?" Tom teased.

Was Tom horny? Harry wondered. They hadn't snuck out to the Ancient Runes classroom in days. It felt like he was trying to start something, but his mood was hard to read. It might just have been another distraction technique.

"Well, I don't miss you bossing me around all the time."

Tom kissed him chastely. It was an unusual move; for once he wasn't shoving Harry back into the wall or onto the bed. He stood there, just letting him participate in the kiss. Harry, surprised but not unwilling, opened his mouth, and slid his hands under Tom's neat button-down shirt, over skin that was suddenly burning hot. He could feel Tom's excitement and pleasure through the bond, and something a little sly too, some exciting thing that Tom was anticipating.

Harry pressed himself closer, thinking about a sofa they had passed a few minutes ago. One of the ornate legs was missing, but they could fix that, he reckoned, or at least prop it up well enough to spend an hour or so snogging on it. Yes, that was just the kind of Saturday morning he would like . . .

But just as he was about to suggest this, Tom pulled away.

"What's wrong?" Harry asked.

"I can feel something."

"Is it my cock digging into your leg?" said Harry, who wasn't interested in anything else Tom might be feeling at this point.

"No," Tom said, letting go of Harry. He strode around the little clearing, poking his head into an old dresser and kicking the trunk filled with plates so that it rattled and fell over. "I can feel something, but I can't tell what direction it's coming from."

Harry realised, with a sudden rush of interest, that Tom was talking about a Horcrux. He adjusted himself in his pants while Tom made several more circuits around the clearing. Just as he was beginning to wonder if Tom could be persuaded to do something fun instead, Tom headed back over to him.

"I think it's that way," he announced, pointing towards the tall stack of furniture to the left. "But I can't work out how to get through. None of the passages go in that direction."

Since the stack was several layers deep and contained a great deal of splintered wood, neither of them really fancied tunnelling through it. Tom gave Harry a boost to get him on top of a wardrobe, and then Harry clambered onto the table that was perched precariously on top of it, grabbing hurriedly onto its edges when it rocked. When his heart rate had slowed again, he lifted his head and looked around. He could see the maze of passages stretching away—and after a while, he found a route that might lead them to the other side. He pointed it out to Tom.

"See that gap down on the right? I reckon we'd be able to fit through that and then circle round."

Tom nodded. Harry was just about to climb back down again when habit made him look for the door to orient himself.

A flash of movement.

Harry froze. It was something much bigger than a winged key; a figure, Harry thought, standing over by the door.

Then he blinked and it was gone. Harry watched for a moment longer, then slid down off the stack, almost falling in his haste.

"What?" Tom demanded.

"They're here."

Tom swore. "Did any of them see you?"

"Maybe," Harry said. "Yes, I think so."

Tom drew his wand.

"No lethal magic," Harry said quickly.

"I won't if they don't," Tom said, then dashed off towards the route Harry had pointed out. They made it to the other side of the stack of furniture without any problems, but then, frustratingly, Tom had to keep stopping to see if he could feel the Horcrux. Harry stood still for the fourth time in five minutes, sweaty hand gripping his wand. He couldn't hear anything unusual, and was starting to wonder if his mind was playing tricks on him. Had he really seen someone over by the door? Could it have been a statue, or a misplaced suit of armour? He hadn't seen their face at all, just their silhouette, and he hadn't seen them move, except in the periphery of his vision.

And if it was Nott and the others, how long would it take for them to find them? It had taken Harry and Tom at least three hours to get to this point in the maze, but they had been moving slowly and chatting, and had doubled back half a dozen times. Nott, Crabbe and Goyle probably knew their way around by now. He watched with rising anxiety as Tom searched a polished cabinet. He didn't seem to be in a hurry. Harry looked at the passage through which they had come, cataloguing escape routes.

"Oh!"

Harry whipped back just in time to see Tom lift a small tiara off the top of the cabinet. It was delicate silver filigree, dusted with glittering white stones. A dark blue sapphire as big as a robin's egg glinted in the middle.

"This is it," Tom breathed. "I can feel it." An intake of breath came as he turned it over. "Look! Harry, look at this inscription! Wit beyond measure is man's greatest treasure." He looked up at Harry with shining eyes. "I think this might be Ravenclaw's lost diadem."

"Yes, very nice."

"The lost diadem is a great Hogwarts treasure," Tom said sniffily. "People have been looking for it for centuries. But I found it—or, Voldemort did, I suppose, but that's basically the same thing. They say it makes you wiser . . . but that it can only be safely used by a true Ravenclaw." He held it up, as if contemplating whether to put it on his head.

"It would look pretty with your eyes too," Harry commented. He was trying not to laugh—a ring, a locket, a diary, and now a tiara? What was next, Helga Hufflepuff's perfume bottle? Morgana's comb?

Tom frowned at him, not appreciating Harry's humour at his moment of triumph. He turned his attention back to the tiara—the diadem. Harry's smile slid off his face at how close his lips were to the gem. He seemed transfixed, gazing down into that deep blue—

"Tom," he said warningly.

Tom seemed to snap out of it.

"Oh, don't worry, I won't absorb it just yet," he said, and to Harry's relief, lowered the diadem. "We should deal with our friends first."

"What—?"

Footsteps sounded. They were very close; someone—more than one someone—was moving just on the other side of the stack. Harry grabbed Tom's sleeve. "Let's go."

Tom turned to him with eyebrows raised. "Why?" he asked. "You can't possibly think they're a threat to us, can you, Harry?"

Oh.

Tom was fully intending to fight Nott and Crabbe and Goyle, and had been ever since Harry had spotted someone at the door. In fact, Harry thought, with a sudden stab of suspicion, perhaps this had been the plan all along. Wasn't it ever so coincidental that Tom had only sensed the Horcrux after they'd come in?

Had he heard the door open while they'd been kissing?

"You planned this," Harry said accusingly.

Tom gave him a wide-eyed look of total innocence. "Of course I didn't! But now that they're here, wouldn't it be simpler to meet them head-on, rather than running? We can find out what they know—they might have heard something Malfoy didn't—and then modify their memories and let them go."

He slid the diadem over his wrist and stood there with his wand casually at his side. He looked bright and excited at the prospect of a fight, and reluctantly, Harry understood the feeling. In truth, he felt an echo of it himself—it had been so long since they'd duelled together. He tucked himself into the shadow of the cabinet, where he wouldn't be immediately evident to the intruders, and waited.

They didn't wait long. A few moments later, Vincent Crabbe and Theodore Nott, both red-faced and breathing fast, entered the little clearing. Their wands were out, but they stopped at the threshold. From the expressions on their faces it was obvious that they hadn't expected to see Tom there, spinning the little tiara on his arm and obviously lying in wait for them.

"Hello gentlemen," he said.

"What are you doing here?" Nott demanded, pointing his wand at Tom. He was tall and dark-haired like Tom, but not nearly so handsome. His weak chin quivered nervously when he clocked Harry standing beside the cabinet.

"Were you expecting someone else?" Tom inquired.

"I thought it might be Draco," Nott muttered. His eyes flicked to the diadem, the glittering treasure that they'd been hunting unsuccessfully for weeks.

Tom smiled, and without warning, struck. A minute twitch of his wand and a fizzing purple curse shot from the tip. Nott summoned a shield just in time. Crabbe gave a belated shout of fury and levelled his wand at Harry.

"CRUCIO!" he bellowed.

The spell missed by a solid two feet, much like his Bludgers in Quidditch. Crabbe barrelled towards him—Harry dodged one clumsy fist, then another, then managed to get off the incantation for a Stunning spell. Crabbe didn't shield or sidestep—just stared stupidly at the red light right up until the moment it hit his round, dim face, then fell on his back like a felled tree. Harry shook his head, then looked up to see how Tom was doing.

It wasn't a pretty sight. Tom had Nott backed up against the tall cabinet. Nott's shirt was smoking and his wand was trembling in his hand. Tom was repeatedly breaking his shield, leaving a bruise here, a cut there, a burning floor that made Nott flinch and jump. Nott's eyes were wide with terror.

Harry coughed.

Tom glanced at him, sighed, and then cast a spell that made skeletal arms shoot out of the cabinet, grabbing Nott's clothes and limbs to bind him tight to the wall. Nott cried out in terror and tried to pull himself away but the bone-white fingers tightened, digging tighter and tighter into his flesh until Nott's wand dropped from his hand. Tom scooped it up off the floor and gave it an experimental twirl.

"Are we done?" Harry asked, looking distastefully at the arms binding Nott.

Tom turned to meet his eyes. His face was slightly flushed, with enjoyment rather than exertion. "Yes," he said.

And shot a spell at Harry's legs.

Harry stepped aside out of pure instinct. The jet of light missed him by a hair.

Had it been an accident? A joke? But Harry knew, deep down, that it was not, and then Tom was raising his wand and casting again—

"TOM!" Harry bellowed as he leapt out of the way of a Stunner. "Hey, Tom—!"

Tom didn't respond, although there was a liveliness in his eyes that Harry didn't like. Harry glanced at the diadem, which was still dangling from his elbow like an outsized bangle. Could he have been possessed by the Horcrux? Was it in control right now?

But Tom's eyes were still brown—

"What are you doing?" Harry demanded.

"What does it look like?"

Harry swallowed. He knew that Tom had meant for his first spell to hit, but now it hadn't, he was interested. Crabbe and Nott had been no challenge at all, and Tom was still itching for a fight. He wanted to see if he could pit his skills against Harry and win.

Alright, Harry told himself, trying to slow his breathing. He didn't know what Tom was playing at, and although his mind was spinning with possibilities, this was no time to speculate.

Tom had lowered his wand and was standing in almost preternatural stillness. Harry knew that he was waiting for an opportunity, for Harry to blink, for his attention to flag. Harry matched him breath for breath; one, two, three—

Tom cast, wand tracing out an arc in the air. Harry parried at precisely the same moment—his shield expanded like a shimmering soap bubble, and Tom's curse splattered harmlessly against its surface. Harry was about to send a Stunner back, but Tom's second spell broke his shield before he could complete the incantation. Harry swore and stepped back, heading towards an opening he knew was somewhere to the left.

"Confringo!" Tom shouted.

The Blasting curse was aimed at the stack of books that formed the wall behind Harry. Pages exploded into the air; the stack buckled at its centre and began to collapse, toppling forwards onto Harry—

Harry turned his back on Tom, dashing towards the opening. A book struck him on the head, and another on the small of his back, but then he was through and around the corner. He raced down a narrow passage, hearing Tom's footsteps just behind. A half-second later, a hex flew over Harry's shoulder. Harry spun, already conjuring another shield.

Tom let fly a barrage of spells, wand sweeping in the fluid movements that were his signature. The incantation for an animation spell, which turned immediately into the half-arc needed to cast the Knockback jinx, then a second jinx that Harry didn't recognise. He flattened himself against the wall as it passed; cursing the cramped space. He was surprised that Tom had things in his arsenal that he hadn't seen—but then, he'd been reading, hadn't he? All those horrible books he'd had in Grimmauld place, stolen out of the bin bags in the drawing room.

Harry backed away under the onslaught. When he sensed open space behind him, he leapt, just as his shield shattered into a thousand fragments.

How do you run from someone who has you on a thirty-foot leash?

Tom emerged from the passage, and Harry whirled to face him. He knew that he had to go on the offensive. Tom's weakness was his defence—his shields weren't as good as Harry's, and he was a fraction slower to dodge.

The problem was, Tom knew this too. It was why he kept hammering away at Harry's shield, not giving him an opportunity to respond. He twirled his wand in his hand, and molten iron sand spun through the air like a jet of water, which formed into a snake that leapt at Harry's throat. Harry grabbed an antique writing desk and heaved, tipping it onto the snake. He looked up just in time to see a jet of white light coming right at him—it hit him in the chest and flung him backwards into a wall. Harry flopped onto the ground on his front. White-hot panic surged through him—he heard a scrape and forced himself to roll, ignoring the sharp pain in his hip, his back. A curse hit the spot where his head had been.

Harry rolled again, and miraculously found himself with a clear view through the wall of stacked furniture—a gap that hadn't been visible at eye level. Harry glanced up, saw Tom coming for him, and wriggled into it, pulling himself through in a mad scramble. His forearms scraped against splintered wood, the knee of his trousers tore on a sharp edge, but then he was through, just before a spell whizzed after him. Harry picked himself up, noting that his wand was still, somehow, in his hand, and looked at the dividing wall.

It was about three feet thick and ten feet high. Harry backed away from it. Tom was silent on the other side—Harry imagined him standing there, contemplating the problem.

Harry glanced left and right. He was scared, and his hip hurt and his forearm was bleeding, but more than all of that, he was angry. How could he have got himself into this situation? No one else knew he was here! Not Ron, not Hermione, not McGonagall or Dumbledore . . . probably no one would come and look for him for hours. The only person outside the Room was Goyle, and he certainly wouldn't be calling a teacher on Harry's behalf. No, if Harry wanted to get himself out of this, he'd have to do it himself—

That was the moment when Tom exploded the wall.

Harry let out a cry of surprise. He shielded by instinct—later, he would have no conscious memory of casting the incantation, but he must have done it, because it expanded from his wand, protecting him from the vicious splinters filling the air. Tom had done something with fire, he thought wildly—there was smoke, the wreckage was smouldering—

Remembering the cloak, Harry snatched it out of his shirt and pulled it over himself. With it came an instantaneous flash of memory; Tom wearing it in the empty classroom, making Harry grab for him, then pulling it off and kissing him—

As the smoke cleared, Tom emerged from the jagged hole, wand raised. A frown crossed his face when he didn't immediately see Harry.

Harry pointed his own wand at Tom under the cloak and thought, Expelliarmus.

It was his best wordless spell, the one that came most naturally to him.

Tom saw the red light in his peripheral vision. He began to shield, but before he could complete the movement, his wand was ripped from his hand. Harry reached up, wanting to catch it as it spun end-over-end in the air.

Then a blast of percussive force hit him and Harry was thrown back, hard enough that his feet left the ground. He crashed down on his back on a pile of curtains. Tom was holding Nott's wand—he'd used something wide-angled and destructive, something he didn't have to aim too precisely.

"Dragon heartstring," Tom commented, inspecting the wand with interest. "A bit boring, but not lacking in power." He looked in Harry's direction, and with a flash of horror, Harry realised that his foot was sticking out from under the cloak. He wrenched it back, but it was too late. Tom summoned a stream of opaque yellow liquid—paint!—which splattered over the cloak.

Harry pulled the drenched garment off, glaring up at Tom. Tom grinned and motioned encouragingly with his wand, letting him get to his feet. There was a small cut under his eye, probably from a flying splinter, but he looked in better shape than Harry felt.

"It's been a long time since we fought for real," Tom said.

Harry met his eyes stonily. He wasn't going to give Tom the satisfaction of hearing him beg for answers.

Tom made a sweeping motion with the wand. Harry shielded, but the spell wasn't aimed at him. It left Tom's wand in an arc, blasting furniture, books, and heaped material backwards until it formed a rough circle around the two of them. There was a grinding sound as a thousand years of history compacted, forming a thick wall with no exits.

"Flipendo!" Harry shouted, while Tom was distracted. Tom blocked the jinx lazily.

He shouldn't have underestimated Harry. A second jet of light flew right after the first, cast silently. It broke Tom's shield—and Harry saw the shock of it jolt up his arm. He gasped in pain.

"STUPEF—"

"Crucio!"

Tom was quicker. Harry dived, tucking into a roll to avoid the curse. He came up onto his knees and cast again without even looking. He could feel the anger surging through him, formed into something hard and sharp like a blade. He forgot his fear, the pain in his back, everything but the magic thundering through him. Tom must have been feeling the same way; there was a wild grin on his face as he animated a golem made of old stones, transfigured a mop into a silver spear. Harry caught it and sent it right back at him, then set the rug beneath Tom's feet alight.

It was like singing, like learning to read, the moment when all the separate parts came together into one beautiful whole. Tom couldn't hit him, Harry thought wildly. He was just too fast, too used to Tom's fluid style. He grinned cheekily at Tom after a spectacular dodge.

Tom wasn't grinning back.

"Avada Kedavra!"

Green filled Harry's whole vision, and he could hear the sound of wings, like a whole flock of pigeons taking off from Trafalgar Square. Harry sidestepped at the last moment and it whistled past him. He could feel it, like a gravitational field, a pull that tugged on his chest.

The last thing his mother had ever felt.

He stared at Tom.

"What?" Tom said. He was spinning a wand in his hand—his own. He must have picked it up off the floor when Harry wasn't looking. "The Killing curse is no threat to you—the worst it'll do is knock you out of your body. You'll be able to get back in. There are no real stakes here, Harry."

Harry's pulse was pounding in his head, so loud he could hardly hear Tom's words. He was so rattled, so angry—no, Tom wasn't trying to kill him.

Tom was trying to upset him.

The next time Tom sent a Stunner at him, Harry met it with an Incendio. Tom hissed as heat strafed up his arm, setting his sleeve aflame. He doused it with Aguamenti, then shot another Killing curse at Harry, who dodged.

Tom took a few steps backwards, watching Harry warily. His arm was burned—Harry could see the reddened skin beneath his smoking sleeve. Ha. Good luck getting Harry to heal that.

Then Tom took another step backwards, and another. The smile fled Harry's face as he realised what he was doing. He leapt forwards, but too late—the pull of the bond came when he was midstride! They both doubled over, but Tom was prepared for it and Harry was not. A jet of something red—and oh fuck, oh fuck, Harry hadn't heard the incantation, and was too off-balance to dodge—

It was the Cruciatus curse, of course. Tom's favourite. Harry screamed, landing on his side and twisting inwards, contorting, as if he could somehow protect the soft and vulnerable parts of himself from the scouring agony of the curse.

Then it was gone. Harry sobbed in relief but managed only one breath before his ankles snapped together, bound with black cords. He saw Tom's shoes, now scuffed and singed, approaching him, and then he was kicked onto his back. Tom bound his wrists in front of him, then stooped to pick up Harry's wand, which had rolled under a nearby footstool.

"That was regrettable," Tom said, although he didn't sound like he regretted it.

Harry didn't reply. All of the fight had gone out of him. His shoulder and hip hurt, a stinging, aching pain, and he could feel exhaustion weighing on him, as well as the residual trembling of the Cruciatus curse. Tom must have been just as tired as he was, but you wouldn't know it to look at him. There was a horrid smug smirk on his face.

Tom might not have planned this, but he had definitely enjoyed it.

Harry laid his cheek against the floor as Tom went around putting out the various fires that their duel had started. Then he blasted a hole in the wall of smoking rubble and levitated Harry into the air. A few moments later, he was dumped on his knees in front of Nott, who was still bound to the ornate cabinet. It must have been sturdier than it looked—Nott's wrist was bleeding, a slow drip drip drip of blood onto the floor below. He'd obviously struggled during Tom and Harry's duel, but the bonds had held.

"Theodore Nott," Tom said slowly, as if weighing the name on his tongue. "I knew your father . . . or perhaps your grandfather."

Nott said nothing. He looked terrified.

"Voldemort has you doing a little mission here, doesn't he?" Tom continued, as he unzipped the red rucksack and took out the diadem. Harry hadn't seen him put it away. "Do you see this?" he asked, holding it in front of Nott. "Do you know what it is? This is the thing you've been looking for, Theodore."

Nott's eyes focussed on it.

"What were you supposed to do with it, if you found it?" Tom said softly. "Send it back to Voldemort in the post? No, don't be silly. Dig a hole and bury it? Of course not. Hide it somewhere else, somewhere more secure? No, I doubt you three would have been trusted with something like that—I wouldn't trust you to outwit Rubeus Hagrid, let alone Dumbledore."

"Please let me go," Nott whispered. It was the first time he had spoken, and his voice came out high and reedy. "I won't tell anyone about you. You can have that thing if you want, I'll just pretend we never found it, please—"

"You have a Portkey for it, don't you?"

The words hit Harry like a physical blow, and he slipped off his knees onto his bum. Of course. Of course. That was what this was all about!

Nott's eyes widened.

"You do," Tom said. "I know you do. I want to know what it is. I want to know how to activate it." He wrenched Nott's head back by the hair so that he could look directly into his eyes. "Don't even think about blocking me," he crooned. "If you do, I'll have to be much less civilised. Cut you, maybe. Burn you. I'd like that, but you won't."

Harry twisted his wrists in his bonds as Tom sank into Nott's mind. His tiredness was wearing off. He didn't think he could get out, unfortunately, at least not without a sharp edge of some kind. Harry scanned the surrounding area. There was plenty of paper on the floor, torn pages and books, but nothing sharp. Then his eyes were drawn to two nails sticking out of a nearby box. If he could only shuffle over there . . .

He moved awkwardly towards it, but before he'd made it three feet, Tom's laughter broke the silence. It was loud, appreciative; the sound made Nott shrink back against the cabinet, blinking rapidly.

Fuck, that was quick.

"Clever," Tom said. "So clever. It's such a perfect solution; so natural, so neat. I had wondered how it was possible that you could have brought a Portkey into the castle, but now I understand. You didn't need to bring anything . . . because one was already here." He turned around, and didn't seem surprised to see that Harry had moved. He came and crouched in front of him, holding the diadem before his eyes. "Don't you see, Harry? Isn't it clever?"

"What, you fucking Horcrux?"

"Not just that," Tom said. "It's the diadem, Harry. The diadem is the Portkey. Nott was supposed to find it and activate it, taking himself and the Horcrux to the Portkey's destination, which happens to be an ancient stone circle in Cumbria. There's another Portkey there that will take him directly to Voldemort."

Tom looked so excited. He squeezed Harry's shoulder, as if inviting him to share in it. Harry couldn't. He felt so upset, so lost and betrayed and confused.

"You didn't have to do this," he said in a little voice. "I promised that I'd help you escape. I wouldn't have stopped you from taking the Portkey."

"No," Tom said, looking first at Harry, then down at the wands in his hand. Holly and sycamore. "I know you wouldn't have. And I know that what I've done here today, I'll pay for."

"So then why—"

Tom met his eyes, and for a long moment they just stared at each other. There was an expression on Tom's face that Harry couldn't read. Something shifting, hard to pin down.

"You wouldn't have stopped me taking the Portkey," Tom said. "But you would have stopped me taking you."