When she was a student, winter at Hogwarts had been its own kind of wonderful. The forest all trimmed in white, the lake iced over, the snowball fights in the courtyards between classes. She had a particularly fond memory of Fred and George charming snowballs to bounce off the back of Quirrell's turban, which would've been Voldemort's face at the time. (She couldn't rightly remember if that was her own memory anymore, or if that had been one of the stories Harry had told her.)

Winter at Hogwarts as a teacher was both wonderful and awful. There was the much-needed break from teaching and students, but that also meant a break from routine that she had to fill with other things. The cold that seeped through the old stones bothered her the way it hadn't when she'd been a teenager. And the ghosts from the war—so many child ghosts, most of whom she at least recognized from her own time as a student—tended to make her sad at Christmastime the way they didn't during the rest of the year.

"Professor Granger," the headmaster said, appearing behind her in that way of his.

"Headmaster."

"Not being nostalgic, I hope."

"I am always nostalgic on Christmas Eve." She turned so she could see him properly. "It's tradition."

He snorted through his nose, which was his version of Molly Weasley's "pish tosh." She'd told him that once and he'd laughed before he could help himself.

"If you truly wish to wallow in old memories, get the elves to bring you hot chocolate in the library."

"Madam Pince would never have allowed me hot chocolate in the library."

"True, but she can't bar you from it now. And you look cold."

"Winter eats through me like it didn't when I was a student."

"Yes. Such age. Surely, you will turn brittle and fall apart. I'll have to acclimate somebody else to the supply cupboards then," he said, sarcastic. "How tedious."

She shot him a glare, but took up his suggestion and headed for the library. It was true enough that Madam Pince couldn't tell her off for having a mug of hot chocolate so close to the books, not only because she was the deputy headmistress now but because Pince had gone to her sister's for Christmas.

"Has the castle ever been this empty at the holidays?" Hermione asked once they'd settled in the library. It was much warmer; the elves had kept the fire going near her favorite reading alcove. She made herself comfortable in the wingback she preferred, her feet propped up on the ottoman near the fireplace. Her knee, which had ached in the cold since the war, began to hurt less.

"Not in living memory," the headmaster said, comfortable in his usual place next to the fireplace. The warm red light glinted off his silvered hair as he gave the impression of both leaning against the mantle and looming over her. She'd stopped trying to get him to knock it off years ago, and had gotten her own revenge for his obnoxiousness by ignoring it entirely; before long, he would make himself more comfortable without the looming.

"And in yours?" she teased.

He rolled his eyes. "No, Granger. It has never been this empty over a break."

She shrugged and looked at the fire instead of him. Her eyes were probably dancing impishly or sparkling with amusement or something, and it would get on his nerves if she looked at him directly. He was amusing, though. In his own way. Once she'd gotten past his prickly exterior and begun paying attention to his actions instead of his words, they'd got on very well.

"What do you like to do when the castle is so empty?" she asked. "I so rarely see you around during these breaks from the routine of teaching."

"I do much the same thing. Wander the halls, wondering what I did to wind up here."

"You don't have to make it sound like such a prison sentence," she said, a bit miffed. "Some of us chose to end up here, you know."

"Yes, I know. And I think you are utterly mad."

"You always say that, Severus."

"It remains true."

She rolled her eyes and let the conversation go for the moment. The fire was very nice, and the hot chocolate was as good as she remembered it. The company was good, too. The headmaster was always good for some needling, or, if he wasn't in the mood to be annoyed (which was rare, but did happen), a proper conversation about Potions. He didn't get to brew these days, so he was by turns annoyed that she devoted so much time to it and glad for the chance to talk to somebody current in the field.

Their friendship had begun with daffodils. They were her favorite flower, and he'd had the house elves deliver her a planter full of them for her office. He'd gone on at length about the planter itself, formerly his own, charmed to keep the plants alive and well even in the depths of the dungeons. She'd made some comment about how she didn't recall seeing it in his office, and he'd been spiky for the full afternoon before settling down to tell her he'd had it in his study, where he hadn't had a need to intimidate students regularly.

More flowers had followed, though it had taken her a very long time to realize he was giving her flowers, per se. Tulip bulbs (potions ingredients), and blooming lilacs from a bush that had grown in the same soil as a venomous tentacula (also for potions use). And roses—oh, the roses. She'd yet to learn where he got them from, but the house elves delivered them every Saturday morning without fail, and she spent her afternoon removing and crushing the thorns, chopping the stems, dehydrating the petals. The roses were her favorite part of her school week routine, smelling so nice while she worked with them before she spent her evening up to her eyebrows in student essays.

After the flowers, there was the jewelry. They'd been working on a charms project together—satisfying their mutual curiosity more than creating new and spectacular things—and the final product had been anchored to a pendant on a long chain. The pendant was mother-of-pearl, gleaming and opalescent, and the chain was delicate gold. It was a beautiful piece, and it hadn't occurred to her to ask him where it had come from. The charms they'd put on it protected the wearer from a slew of low-level curses, warned them if they were about to activate a malicious ward, and turned it into a touch-activated Portkey that would bring her to her office (utterly convenient when she forgot something).

A simple gold bracelet to match the pendant's chain had appeared in her jewelry box the week after they'd finished the necklace. The house elves had refused to fess up, and he'd been even less forthcoming. She'd worn the set almost daily anyways. He always seemed pleased.

She'd found the arm band—silver inlaid with turquoise—in one of the drawers of her classroom desk. At first, she'd assumed it had been Slughorn's (since he seemed much more the type to have such a shiny thing), but the headmaster had gotten so huffy when she'd brought her suspicious up that she knew better. It was surprisingly useful, too, for something so pretty: it fit just below the bend of her elbow, and had an Undetectable Extension Charm on it, allowing her to slide her wand in the place between the band and her skin, hiding it away when she wasn't using it but keeping it easily to hand even when she wasn't wearing sleeves that could hide her usual wand sheath.

"You're ill," the headmaster said, interrupting her thoughts.

"Excuse me?"

"You're ill," he repeated. She pursed her lips and glared at him. "You are."

"It's really none of your business," she said.

He snorted that "pish tosh" snort again.

"You fell asleep just there."

"And why shouldn't I?" she asked, defensive now even though it was a troubling thought. (Maybe defensive because it was a troubling thought.) She hadn't meant to fall asleep. She hadn't even felt tired. And she hadn't noticed that she'd fallen asleep or woken up.

"You are too young for naps like those, Hermione." He looked her over critically, scowling. She could see the concern in his eyes, though.

She looked away, watching the fire for a moment. It had burned down a bit, but not much. He let her have her moment, calling a house elf to take care of the hot chocolate she must've dropped when she'd nodded off.

"Are you going to tell me what's wrong?" he asked.

"I don't know," she said. "And before you get touchy, the Healers don't know either."

"That's why you went to Bermuda," he said.

"Yes. I was seeing a specialist."

"How can there be a specialist if they don't know what's wrong?"

"I think they were just trying to give me hope, really. Go see the expert in the wonderful, sunny place. You know?"

"Yes."

She shrugged. "It's from the war. Some people have these lingering things, and some people came through alright."

There wasn't much to say to that. She rested her head against one hand and looked at the fire. They were silent a moment.

"You fell asleep again," he told her. The fire had burned down completely, and the moon was fully visible out the window.

"It was a good nap, though," she said. "I feel better than I have in years."

She stood and stretched. Putting her feet up and keeping near the warm fire had done its trick on her knee; it didn't ache at all. There wasn't that dull pain in her chest, either. She barely noticed it anymore on top of all the other little things, and especially because she'd had it since the Department of Mysteries affair at the end of fifth year.

"I didn't realize it was as bad as that," he said. He was closer to her that she could remember his being, standing almost within reach instead of looming over by the fire.

"It isn't that bad," she said. She rolled her shoulders, trying to call up a mental list of all the things she should try to take care of before her knee started bothering her again. Strangely, she couldn't bring anything to mind.

He stepped up to her, close, and she waited for the shuddering cold that came from proximity to any ghost. But it didn't come. He pressed a few fingertips gently, tentatively, on her cheek, and then his whole hand.

"What—" she started, looking back behind her at the chair. She hadn't risen from it at all; she was still sitting there, her head propped up by her hand. She looked like she was sleeping, but there was something in the droop of her shoulders that told the truth.

"I didn't think it was as bad as that," he repeated, turning her around to face him again.

"I didn't think so, either," she said.

They stood together like that for a moment.

"You're awfully young to have died," he said.

"I'm the same age as you when you died," she pointed out. "And I'm not nearly so young as most of the ghosts in this castle."

"You are, in fact," he said, "the youngest ghost in the castle."

"I know for a fact that there's a twelve-year-old who haunts the Charms corridor."

"That's Logan, and he likes that corridor because there's always a first year or two who get turned around going to Defense and end up there, even after several months at the school," he said. "And Logan is a thirty-year-old ghost. You are, in fact, not even five minutes old."

"So that's how it is, hm?"

"Yes."

"I always wondered what that boy was up to. He avoided me."

"You were a professor. It would give away the trick."

"And you were the headmaster."

"Yes, but I was here from the beginning for them."

"You've been here an awfully long time."

"And I suppose I will continue to be," he said. He moved toward her again, taking her hand. It was warm.

They left the library. He held her hand as they passed through walls and then drifted down through the floor to reach her office. Her daffodils were there, cheerful and yellow. She reached for one of the blooms, as was her habit, but stopped herself when she remembered that she'd be too cold to touch it now.

"Is that why you always stayed across the room?" she asked, looking from him to the daffodil and back. "You didn't want to make me cold."

"Of course."

"And is that why you've stayed so close this school year? You knew I was…"

"No, Hermione," he said. Something about the way he said it warmed her from head to foot, and she wondered how close he'd let her get now that he wouldn't make her cold. He changed the subject before she could do more than take a step toward him, though: "Now. Is there anything in here that you'd like the elves to destroy before they alert Sprout that the deputy she left in charge of the castle over the break has passed away in the library?"

"What, you mean pornography under the mattress or illicit potions in the store cupboards?"

"Yes."

Hermione laughed. "No. There's nothing. It will be Harry sent to clear out my things, and he already knows everything in my diary. And I kicked the Dreamless Sleep habit years ago."

"Will you humor me for a moment, then?"

"Humor you?"

"Yes. I'm allowed a bit of Christmas Eve nostalgia of my own, you know."

He wouldn't say another word on it, just led her though the castle by her hand again. He brought her to the Charms corridor where Knightly, the Charms professor, had put up a sprig of enchanted mistletoe. Hermione had heard more stories of students trying to avoid it or trying to break the enchantment without a kiss when they were caught beneath it than she cared to recall.

"The mistletoe?" she asked when he paused just outside the range of the charms.

"You were caught under it the first year you taught," he said. She nodded, smiling at the memory. She'd kissed a first year on the cheek to get out from underneath it, laughing heartily at the dread on the little boy's face when he'd first thought he'd been caught under the mistletoe with a teacher and she'd been about to plant a wet one on him. It was one of her fondest memories of the castle.

"Poor Mister Avery," she said, still smirking to herself.

"Logan told me about it, and the thought never really went away," he said, then stepped beneath the mistletoe. The charm wouldn't really work on him since he was a ghost, but that was beside the point. He held a hand out to her.

"A proper kiss this time, I think," she said. He smiled.