Summary: It begins and it ends in fifth year, but without Death there can be no life. During the hunt for the Horcruxes Harry receives news he is not sure he can believe. And even if he does, it was never easy.

Pairing: Harry/Sirius

Rating: M

Warnings: SLASH. Underage (15/36), godson/godfather, angst, allusion to minor and major character deaths, death themes in general.

Disclaimer: The world of Harry Potter belongs to J.K. Rowling.

A/N: This is a bit of a new format for me. We will have some time jumps and some chapters will be longer than others. In total there will be seven chapters and I'm planning weekly updates. Also – fair warning – this gets pretty dark in places but (spoiler!) I promise a happy ending. Finally, I hope you will enjoy it.

Unto the Haunted

Chapter one – Succumb

Later, when he will try to conjure the memory of those initial, agonising minutes before it finally happened, the first thing he will remember is that little glass figurine in the shape of a unicorn. Of all things! He will lie in his bed in his Hogwarts dormitory with his curtains firmly jerked closed around him and think back. He will let himself drift back to that afternoon and the first image that will pop into his head will be of that unicorn, sparkling like running water. Like clear quartz.

But right now, Harry is standing in the doorway to the old study in number twelve, Grimmauld Place, wondering if he will ever survive this.

"Muggles believe in them, too," says Sirius.

He has followed Harry's gaze to the figurine. The cold January light breaks into the windows and cuts through the glass, making an entirely new splash of light underneath the unicorn's hooves.

"Not all Muggles," says Harry. He is pretty sure Uncle Vernon does not believe in unicorns. Aunt Petunia might (seeing as her sister was a witch) but if she does that is not something she is likely to ever tell another living soul.

"Their loss." It comes out somewhat flat.

Harry hesitates on the threshold. Sirius is over by the window, the massive wooden desk separating them. His godfather is pale and his grey eyes are on Harry now, intent. He is watchful, Harry realises. Leaning back just a little. Not giving in.

So it is Harry who takes a step closer and it brings him over the threshold and into the study. He can see it now: the tension in Sirius' shoulders, the rigidity in his frame.

He knows, just as Harry does. That this is it.

In three days' time Harry and Ron and Hermione will be leaving for Hogwarts and most likely a new onslaught of decrees and stupid rules that Umbridge will use to torment all the students she hates. Hogwarts is not the place he once knew.

"Harry…" It is a clear warning. Sirius' voice sounds a bit tight.

They lock eyes. From the stairs, or the landing below, comes a thud and there is the sound of voices. As if Hermione and one of the Weasleys have decided that now is the moment to come to the rescue. Because, really, it is. Now would be the perfect time to stop whatever is going to happen from happening. And then they – Harry and Sirius, that is – can pretend that nothing at all is going on.

Harry closes the door. It shuts out the voices and if the air in the dank study had been moving before it now comes to a complete standstill. Sirius looks as if he wants to say something but he only manages a wince.

He is very handsome, Harry thinks. He is wearing a plum-coloured, button-down shirt and black trousers, and his dark hair falls in soft waves around his face. He is unshaven and tingles speed through Harry's stomach as he imagines touching those cheeks. It is not something he ever thought he particularly would want to do but over the past couple of weeks he has had a hard time dismissing the idea.

Above Sirius' head, a garland of evergreens is looped around the curtain rod. All in all, barring the attack on Mr Weasley and the fear that stirred up, this has been the best Christmas of Harry's life.

He takes another step and something moves over Sirius' face. Fear, perhaps? Anticipation?

"Harry…" Strangled, this time. Sirius licks his lips. "Don't."

But he has to. At the very least he has to try. He cannot not try.

Sirius, valiantly, makes a new attempt. "You don't know what you're doing."

That much is certainly true – Harry has absolutely no idea how to go about these things. It is just that Sirius has spent the entire Christmas break with his eyes fixed on Harry and sometimes his lips slightly parted. He has been looking in a way no respectable thirty-something-nearing-forty-year-old godfather should be looking at his fifteen-year-old godson and it has been making things to Harry that he does not know how to think about without blushing.

That is why they are here now, with no more than three short days until school starts and with Harry closing the distance between them.

"Don't you want this, Sirius?"

It is probably a little bit unfair.

The older man looks pained. Haunted, almost. "It doesn't matter what I want, Harry. It's wrong."

"I don't care."

"Everyone else will care."

"I don't care about that either."

Harry circles the desk and so comes to stand face to face with his godfather. Through the grimy window he can see a corner of Grimmauld Place and the bare, greyish-brown bushes in the shoddy square. He prefers to look at Sirius.

His godfather is several inches taller, with lines around his eyes. He has high cheekbones and a chiselled chin. In Harry's presence he seems unable to keep his shirts buttoned all the way up to the collar.

They are close now, simply staring at each other. Harry has chosen his jeans with care. They were once Dudley's (of course) but not too ill-fitting. They sort of hang on his hips but he reckons that might be a good thing right now. His t-shirt is old as well, and perhaps half a size too small. By the way Sirius' grey eyes burn into him he suspects that is not a problem.

That gaze, however, makes his throat go dry.

"If we do this…" His godfather keeps his voice down. Like that, it becomes a rasp that smooths itself over the bare skin of Harry's arms, making him shiver. Sirius leans in just the slightest. "There's no going back."

Harry nods, not really knowing how to tell him that he never would want to go back. That he never wants to live a life without Sirius. In fact, he can almost feel the way the world is tilting a little sideways. How he is actively choosing to change everything.

Sirius' face is very hard to read. There is a twitch that really has nothing to do with a smile in the corner of his lips. Then, to a whoosh through Harry's stomach the other man, too, nods, but grimly almost. "I'll take you upstairs."

"No." Harry cannot say precisely why he refuses. Probably, because he is afraid that climbing several flights of stairs will give Sirius time enough to change his mind. "Here. I want it here."

His godfather's eyes go a little wide and a furrow appears between his dark brows. "Harry..." He sounds shocked. "What do you mean?"

As if he does not understand.

"I don't want to go upstairs."

Harry does not have to look at the desk, Sirius does it for him. He is even paler now, tense around the jaw and mouth. "We can't," he says, sounding like he's forcing the words out. "I can't."

"But you want to." He hopes. He's pretty sure he knows but that frown in his godfather's face is still firmly in place.

Sirius opens his mouth but then closes it again. He licks his lips. He swallows. "What I want, Harry," he finally rasps out, "is not important."

But it is. Besides, this is all Sirius' fault to begin with. It is he who started it by ogling Harry as if he has become edible since they last saw each other.

Harry does not want to debate this, go into morals and ethics and list loads of reasons for why this would be a terrible thing. He just wants it to happen.

"It is, though," he says, and takes one more, small step closer. They could touch now, if they wanted to. "Do it."

Sirius' eyes are on him, sharp and bright. He is still hesitating, and his breathing looks rather shallow and light. Like his breaths are flimsy and almost unnecessary. Then his hand lands on Harry's hip. His thumb slides under the washed-out fabric of his t-shirt and finds skin. Slowly, he rubs a circle into it, waking it up, making that slow pounding in Harry's body that he has started to associate with Sirius come alive.

The silence around them is thick. Harry looks down at the way his godfather is touching him, then up again, into his lined face. "I know you've done it before," he says, quietly.

He does. At the very beginning of the holidays he climbed the stairs to get Sirius for another round of Wizard's Chess but when he reached the fourth floor landing he had heard voices sifting out from Sirius' bedroom. The door was ajar and the warm glow of firelight spilled out into the gloom at Harry's feet. They were just inside the door, poring over an old photograph, from the looks of it, both of them too immersed to notice Harry in the shadows.

Lupin was repeatedly tapping the picture with an index finger, as if pondering something. His voice was unusually merry. For him it was only a simple question, for Harry it changed everything:

'Was that the night you shagged him?'

Sirius had not looked affronted. Nor did he look surprised or confused or shocked. No, Sirius' reply had been a grin, and one unlike any other grin that Harry had ever seen him fire off before. And he had looked… proud.

Now, Harry watches his face again. "At least once before," he continues. "I overheard you and Lupin."

Sirius winces again. His lips half-form words that never come. He frowns. "Harry…" His voice sounds ragged and breathless at the same time. "It's… It's the only thing I've ever done." Again, he swallows. "I mean, I've only been with men. Harry, I'm gay. I should have told you. Sooner. Maybe. I don't know." He is looking very much as if saying all of this is actually causing him physical pain.

Harry nods. Not because he agrees with that last part but because it is the confirmation that he needed. "It's OK."

"Yes," says Sirius, a little stronger now. Somewhat firmer. "But this is not. This is wrong."

"But you want it." They are still touching. Harry covers his godfather's hand with his. "I want it, too."

Sirius lets out a groan. It comes as a surprise to them both, apparently, for a flush of colour invades Sirius' cheeks and he briefly closes his eyes.

"Please?"

"It'll hurt."

Harry smiles. He smiles until Sirius' other hand comes to cup his cheek and drag a thumb over his lower lip. Until that hand works its way into his hair to hold the back of his head. Before him, Sirius lifts his chin a little, as if testing him. As if he wants to know if Harry can handle this.

Of course he can. They both know it. He has been through worse.

Sirius hesitates for another second – perhaps in a futile bid for redemption – but then, finally, the fight is over.

Their first kiss sets the tone.

Harry loses his breath long before the midpoint, already when his godfather's mouth opens on his and his tongue moves into his mouth. Both of Sirius' hands are in his hair now and he angles Harry's head so that the kiss deepens and deepens and deepens until stars flicker at the edges of Harry's vision. He moves his tongue back and forth against Harry's and when he tires of that, he takes to nibble at Harry's lower lip before he sucks it into his mouth with devious intent, and perhaps some desperation, too. It makes Harry moan and place his hands on Sirius' hips, quite instinctively. His godfather growls, rather, and lets go of Harry's mouth so that he can kiss his way down his throat. He uses his teeth, even, to rasp against the skin and he leaves little marks and memories there. His breathing is hot and deep.

Harry holds on to him, barely feeling the floor under his feet. His head is swimming. All of their own accord, his hands find their way underneath Sirius' shirt and he shivers as he touches bare skin. Sirius' hair tickles his cheek, Sirius' scent is all around him and his blood is coming to a boil.

"Off."

When his godfather pulls back, he looks changed. His pupils are blown. He looks wild. He is tugging at Harry's t-shirt. "Off," he says again. It comes out in a low growl.

Relieved that his brain is still functioning, Harry obeys, working the t-shirt over his head without dislodging his glasses in the process. A hardness crashes into Sirius' face as he drinks Harry in, but he is too far gone at his point; he is already on the road to wherever they will end up and any reminder that his godson is not yet of age lacks the power to stop him now.

He lifts a hand to Harry's chest and his fingertips dance over one dark nipple. Then he cups Harry's shoulder and spins him around so that he ends up with his back to Sirius' chest.

"Now…" he purrs into Harry's hair, into his ear, "we begin."

He steps up so close that Harry can feel the hardness against his arse. He can feel Sirius' cock. The realisation hits him like a jinx but is infinitely better. When his godfather grinds his hips against him he cannot help his groan and Sirius' chuckle is dark upon his skin. A wet tongue tip traces the shell of his ear and teeth nibble at his earlobe. It would be enough to make him melt into a puddle on the study floor.

Sirius' arms come around his waist and suddenly he is unbuttoning Harry's jeans. His hand dives into them before Harry has time to say a word and for the first time ever another person is feeling him up. Sirius' hand, with its long, calloused fingers, is palming him and making him squirm. Warmth is flooding him, pushing at him, tearing at him and still Sirius' hand moves over him, never minding that Harry's briefs are still covering him up. His godfather's breathing is ragged now, harsh in his hair but his lips leave kisses on Harry's neck. He works them both towards the desk, silently urging Harry to lean against it, with the edge digging into his thighs.

It does not matter. His jeans are halfway down his thighs now anyway and his pants are following and then Sirius is touching him properly – taking Harry's prick in his hand and stroking – and Harry mostly thinks he will throw up because apparently that is how his body wants to handle this.

It is warm and dry and Sirius' strokes clear the head of his cock from the foreskin. Harry plants his hands on the desk and screws his eyes shut as he tries to deal with every single impulse. Sirius plasters himself to his back, the buttons of his shirt pressing into Harry's skin like a string of small pools of coolness until they warm up and the sensation is lost to him. His godfather coaxes moans from him and liquid, too, from his prick and the friction as it is smeared over him is addictive.

"Do you want me, Harry?" The question rasps itself over Harry so deliciously that he actually whines.

And he nods, frantically.

Heat twists within as Sirius slides a hand between them and Harry feels it on his naked arse and then… Then Sirius' hard cock – and God he feels big – springs up to press into his backside.

"More?"

Always more.

Sirius does magic – quite literally – and causes Harry to choke on a gasp as he feels himself open. Sirius has slicked himself too – or at least Conjured some type of lubrication for there is wetness where his cock nudges at Harry's cleft.

Harry drops his head. Sirius drops another kiss to his neck. Then he bites down. It is not hard but it sends a jolt of lightning through Harry all the same. Sirius pushes and it is done.

It is like flying. Probably. Maybe. Or like something else Harry once upon a time had never tried but now knows he can never live without. Sirius is so deep inside that he can feel his pounding cock from within. His arms threaten to give up and so do his lungs. Sirius pulls out just enough to be able to plunge back in again, as soon as possible. As if his godfather could not live without this either. His hand is still working Harry's cock, now in time with his thrusts, and it makes all the difference: on Sirius' fourth stroke since he breached Harry, Harry comes all over the ancient desk. He does it on a groan that completely empties his lungs and which tears through his throat like air on a really cold day. Though he is far from cold. In fact, he is burning up, exploding, transforming.

Sirius milks him until the end, his mouth on Harry's neck and cheek and wherever else he can reach. Then he moves both his hands to Harry's hips and begins to thrust in earnest. The desk comes up to meet them and Harry clings to it desperately. Sirius is everywhere, in every place, all at once. He is claiming Harry as though – a silly thought – he would ever consider being anyone else's. Sirius has him bent over, splayed and open. It is the best thing.

Outside, for the first time that Christmas, snow begins to fall.

TBC