Happy Birthday.

By Rose Williams.

Rated PG-13.

Spoilers, very vague for the Angel episode Damage (technically.)

Disclaimers, this belongs to Joss Whedon and J.K Rowling, not me.

Author's Note: This was written as a birthday present for my friend KMMG. It's a day late, but oh well. We need more Buffy/Snape fics out there.

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Buffy smiled nervously at the assembled teachers. They were all much older than her, except the dark haired guy at the back, and he was glowering at her.

"I would like to introduce you all to our new Defence Against the Dark Arts professor, Buffy Summers," Dumbledore said.

Buffy waved.

"I can assure you that Ms Summers has the skills and the training necessary to teach the class, despite her apparent inexperience. She has been actively involved in fighting many dark creatures since she was fifteen, and has studied in preparation for the class. I would like you all to make her welcome."

Only Dumbledore and Minerva knew how she had got her experience, and Minerva had been unsure of the plan to hire her. Privately Buffy agreed, but with hundreds of Slayers across the globe now, she wanted a somewhat normal and vaguely interesting job.

The other teachers gathered round and introduced themselves. Hagrid asked if she liked 'in'ressing creatures,' Pomona Sprout asked if she'd seen any of a number of plants.

Buffy just shook her head. Everyone had such fantastic names. She supposed that Summers was a pretty good name for a Vampire Slayer.

The greasy haired man held his hand out to her stiffly.

"Severus Snape," he introduced himself. Buffy resisted an urge to giggle. He was obviously trying to be intimidating. Unfortunately for him, she had suffered under Angelus's tender mercies and simply accepted his hand to shake.

"A pleasure to meet to you, Severus," she said, delighted when he grimaced as if in pain.

"Buffy is an unusual name," he commented.

Buffy snorted. "It means God's promise, or shining one," she said.

She thought both were quite good for a Vampire Slayer, too.

"What does 'Severus' mean?" she asked.

He accepted the obviously insincere naivety with good grace. Buffy thought she saw him repress a smile. But it was difficult to see through all the hair. And Sibyl Trelawney introduced herself.

She eyed Buffy through her large glittery glasses.

"Death is your gift," she breathed.

Buffy decided that no insect-pretending-to-be-a-person would be so obvious.

"Delivered and returned," Buffy said.

Trelawney's eyes widened until they were almost larger than her glasses. Buffy definitely heard Severus snort. Trelawney huffed and gathered her shawl around her before gliding off.

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The grounds of Hogwarts were a glorious place to stroll at night. Buffy hadn't gotten over the need to patrol, even when there was no risk whatsoever.

Firenze had taken to coming out with her and showing her the stars. In all her time outside Buffy had rarely taken the time out to look up. They looked spectacular tonight, so far from city lights, and without a moon.

Firenze seemed equally fascinated by her. His first question had been about Dawn's welfare, and they had spent the last few weeks discussing everything about both their worlds.

"There are spells on computers?"

"Yes, no. There are spells that you can see if go into a computer, and look at what's inside. Maybe. I'm not sure really. But spells and Muggle technology can work together."

"Not in this world," Firenze said. "Perhaps that is deliberate. You are making me think more about my world than I did when I saw only the stars."

He stopped to look up at the stars again. Buffy automatically looked up too. She could rarely see what he did, but he often said something profound as a result of what he saw and she would remember it to add to her Slayer dream diary. It wasn't the first time he had made the comment about thinking more things either. As thankful as Buffy was for his company and wisdom, she had heard Willow's speeches about 'civilising' populations.

"Hmm," he said after a moment.

Buffy glanced sideways at him, but he didn't look at her. She saw his eyes flick towards the forest and he raised an eyebrow.

"If you will excuse me, Ms Summers," he bowed, turned abruptly and galloped off.

Buffy had enough time to wonder where he had gone before she was aware of someone behind her. She turned, arms raised and met the startled face of the potions master.

"What are you doing out here?" she demanded.

"Collecting Moonwort," Severus said.

He even raised the pouch he was carrying as evidence. Buffy suppressed a grin; he was more rattled than she was.

"What are you doing?" he asked.

Okay, so not so rattled.

"I was walking with Firenze," she said.

Severus looked around as if searching for the centaur. Buffy sighed and turned back to the castle. She'd gone four steps before he was back by her side.

"There might be things here that wouldn't attack a centaur, but would make for a young woman such as yourself."

"There are very few women such as myself," Buffy said. "And I can take care of myself."

Severus insisted on walking step for step with her all the way back up the grounds. Her stride was too short for her to outdistance him without running. He even held the door open for her. She rolled her eyes at him.

There was no way she was going to be able to explain to him how she felt when Jenny had died. There was no way he was going to be able to explain it in an abstract and fatalistic manner nearly convincingly enough for her to think about it without getting angry.

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She noticed a distinct coldness in his manner at breakfast the following day, and for the rest of the week. She found herself grinding her teeth as she thought about him. Why couldn't he just do what every other man did and ignore a woman's outbursts. She realised that was probably not actually true, but it didn't help.

Forcing herself to calm down, even employing someone Giles's exercises, she made her way to class.

Classes were, for the most part, pretty good. The students were either interested, scared, or worried enough about their marks to pay attention. Except one.

"Mr Malfoy, you obviously already know everything there is to know about a vampire's power. I could arrange for you to meet Angelus himself."

"What's Mudblood like you know about vampires?" Malfoy sneered.

Every student in her class was suddenly in a different place.

Harry was being held back by Ron and Neville. Hermione had her wand aimed at Draco's chest, but she didn't seem to want to use it yet. Parvati and Padma were flanking her, with several other girls behind them. The other boys had formed a ring around Harry, Ron, Neville, Draco, Vincent and Gregory. Except Blaise who was with Millicent and Pansy, their wands aimed at Hermione. Most of the desks were lying on their sides.

"Everyone back to your seats," Buffy said.

No one moved.

"Do you really have so little faith in my ability to defend myself against the dark arts that I can't take on a skinny sixth year myself?"

The students slowly returned to their places, except Draco who was left standing in the middle of the room with his wand out. Buffy had to deal with him now. She sighed.

"Would you really like to meet Angelus?"

"No, Professor."

"Good, because I don't want to see him again either. You will serve detention with Professor McGonagall tonight and the first three days of next week. I'm deducting 20 house points from Slytherin. I'm not deducting more," she added at the Gryffindors' protests, "because you were wrong in characterising me as a 'mudblood.' Please, sit back down, Mr Malfoy."

Draco sat. Hermione scribbled something on her page of notes. The class continued.

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Hermione cornered her after class two weeks later. Buffy had been waiting for it. Hermione had had the same look Willow had had many times.

"Miss Granger?"

"Ah, could you really have set Angelus on Malfoy?" she asked.

Buffy grinned. "I could have got a close second, maybe. But I don't really want to see him either. What did you want to ask?"

"You said you weren't Muggle-born."

"Yes."

"But if you were born into a Wizarding family you would have gone to school."

"And you couldn't find me in any databases?"

Hermione blushed. Buffy sat on her desk so she could swing her legs.

"But if you were a Muggle there's no way they would have hired you to teach here."

"And the other option is…"

Buffy prompted. She was waiting for the sudden revelation to hit Hermione.

"Well, if you were a magical creature?"

Buffy nodded, accepting the label.

"Female, human in appearance, not a vampire. Not a Veela, or well, anything evil."

"How much thought have you put into this?" Buffy asked.

"Just since you said to Malfoy. I spent the weekend in the Library, but I couldn't find much. I know you haven't used a wand all term, even though you've taught us how."

"So I don't need a wand, even to deal with Vampires and demons."

Hermione blinked a couple of times before refocussing on Buffy.

"You don't look any of the descriptions of the Slayer I've ever read …"

"They're either out of date, or fanciful," Buffy said. "Technically I was only the Slayer for a year, so maybe official records don't have me anymore. But I've done a lot."

"You're really the Slayer the 'one girl in all the world'?"

Buffy got down off the desk, collected her things and opened the door.

"I died for few minutes when I was sixteen. Since then there have been two of us. About twenty months ago a friend of mine tapped into the Slayer's weapon to call all the potentials in the world."

Hermione looked at her blankly.

"Oh Giles would love to have someone knew to practice the speech on. Come on, I'll tell you over dinner."

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Buffy's third confrontation with Severus came soon after dinner with Hermione. She'd made it out of the Great Hall, leaving Hermione behind with a list of books to find in the library. Hoping to train some before having to mark assignments, she'd headed towards the nifty room on the seventh floor.

Severus had taken a shortcut and appeared out of a wall several steps in front of her. Buffy just waited for him to cross the distance. She wasn't going to let him know that she had been avoiding him.

"What do you mean by putting Draco in detention with McGonagall?"

"He obviously doesn't respect me, so the threat is hardly worth the breath. If I spend detention bringing him back into line, he's won something. There is not a soul in this place apart from Peeves who doesn't respect Minerva."

Severus was quite taken aback by her straightforward explanation. Buffy waited for him to recover. It would be fun to see if she could put him off guard again.

"I believed he raised some valid concerns, which you failed to address."

Buffy raised an eyebrow at that.

"I told him he was wrong to describe me as Muggle-born, although the word he used was Mudblood. Other than that, I don't believe he said anything constructive."

"You threatened to feed him to a vampire, Miss Summers."

"I said I could arrange for him to meet Angelus, Severus. He declined my polite offer, insulted me, and questioned my experience. I gave the worst punishment I could think of through the rage. If you'll excuse me, there are things I have to do."

Severus was standing over her again. Buffy rolled her eyes, again, and stepped to go around him. He stepped to block her way again.

"You don't have any experience," he said.

"Professor Dumbledore obviously disagrees with you. I can't assure you that I have seen worse than you have, because I don't know anything about your past. I would appreciate you making the same concession for me."

Resorting to Slayer strength Buffy pushed him out of the way and headed to the room. He jogged alongside her.

"Who are you and what have you seen?" he asked.

"Who are you and what have you seen?" she asked him. "And why should I trust you?"

Severus stopped as if he'd walked into something. Buffy turned to face him. He knew that he couldn't argue that Dumbledore trusted him because it was the same argument he's just refuted. He went for intimidating instead of pleading.

"You can't," he said. "I'm evil."

Buffy chuckled.

"You're can't be as evil as Angelus, and he knew more about me than you ever will. Also, I told Spike things before he got his soul. He knew stuff when he was evil, too. Not to mention my Watcher has an evil demon tattoo on his arm. Could you stop trying to be intimidating, I'm not eleven."

It was Severus's turn to chuckle. He looked reasonable when he smiled, Buffy decided. She toyed with the idea of telling him, but the laughter might have been cut off, so she let it slide.

"Okay, so I was a spy on the Dark Lord."

"I'm a Vampire Slayer."

Severus frowned. Overall his reaction was even as good as Hermione's.

"So there's more than one," he said.

"Since May last year there are thousands."

"No, I mean there was more than one forever."

"One Slayer dies, another called, blah, blah, blah."

Severus looked at her darkly. It was a look Buffy was sure she could get sick of very quickly. Before that could happen Severus stepped past her and disappeared down the hallway.

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Buffy didn't see Severus for several weeks. She knew that he was still alive and grouchy because her students had come into class complaining about him. But she began to get worried about what he was doing. She decided that the only thing to do was talk to Dumbledore.

"I'm sorry, Buffy, I can't just tell you that," the Headmaster said. It didn't help that he seemed amused rather than put out.

"I need an excuse to see him. This is good."

"Severus is an intently private man, Buffy."

"And I'm not … either a man or intensely private. I promise I won't try to offend him. But he is rather touchy, and he thinks he's evil."

She shook her head before continuing. "I have something picked out. Unless I've only got, like, a week, in which case he'll have to made do with half. But I promise I can do non-offending, non-scaring away. If that's what you want?"

Buffy had worked quiet hard at presenting a calm and mature front to the rest of the school. She thought she had most of them fooled, too. Dumbledore, though, was well aware of her reputation.

He steepled his fingers and looked at her through them.

"Have a seat, Buffy."

Buffy sat.

"You've settled in here well, it seems. So I'd to discuss with you a broadening of your duties."

"If you tell me when Severus's birthday is," Buffy said.

She wasn't normally so forward as to make ultimatums to her boss. But this was looking to be a professional negotiation. And Dumbledore, as always, seemed to have taken it already into account.

"I'll also tell you why I keep him around," he offered.

Buffy settled herself for a good story.

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Buffy checked her appearance in the mirror again. It still felt strange to wear robes, even after several months. She tended to wear Muggle clothing in class and to patrol, but Dumbledore had explained Severus's appreciation of propriety. Finally deciding to do up the top button, Buffy turned in a swirl of purple and headed towards the dungeons.

They were dank and slightly mouldy. No one came here voluntarily, certainly not anyone who wasn't a Slytherin. Even the students stayed away from the heavily marked wood that was Severus's door.

Buffy knocked brightly and waited. She could hear Severus shuffling about inside. She knocked again when it seemed he was considering ignoring her.

"I know you're in there," she called. "I can hear you. Open the door!"

Snape pulled the door open and glared at her. Buffy grinned back at him. He really was an amazing man to look at with his dark hair and narrowed eyes. He was staring at her with unbridled suspicion.

"Happy Birthday!"

The suspicion didn't lessen.

"Dumbledore also told me that you're not evil anymore, so I would like to say congratulations. I have a friend who went through a bad patch, so I can understand a little."

"Thanks," Severus said.

"Are you going to invite me in?"

"Do you need an invite?"

Buffy pushed past him into his office. She had expected ornate and dark like the segment on the movie review programs. Instead the furniture was sparse. He had a desk, a several bookcases and a short cabinet; well made, but plain; and a few glass display jars of icky things. It reminded Buffy a little of the basement Angel had had in Sunnydale.

Buffy wandered around the room checking things out. With a start she realised where she was, and why had come there. Turning quickly she discovered that Severus had been watching her.

"I promise I won't break anything. I brought you a present."

"Present?"

"For your birthday."

Reaching into her pocket she pulled out two blood filled vials. She saw Severus's eyes widen. He leant forward to get a better look. Buffy had thought that blood would be a good present, even though he wasn't technically a vampire; skin tone and dungeon living aside.

"This one is the blood of the, well a, Slayer. The second is the blood of the human vessel of the Key of Dagon."

Severus snatched his hand back from where he was reaching for them. He stared at her. She was startled.

"How did you get that?" he demanded.

Buffy shrugged. "I asked for it."

"And the Slayer's?"

She raised an eyebrow at him.

"I'm sorry, I'd forgotten," he said.

Buffy couldn't help but smile. Too many people were overawed, or deliberately dismissive of the Slayer. Few had as little reaction as he had.

He'd gone back to examining the blood, without touching either.

"I don't know if there are any potions with blood in them, Willow always did the chemistry. But I thought, you know, more things in jars that no one else has."

"You know the Key?" he asked.

Buffy immediately stepped into defensive stance at his casual tone. He must have realised exactly what the effect of his words had been because he turned slowly and reached out a hand to place on her arm. Buffy didn't relax. But she was aware that no one had been in a position to hold her arm like that, warm and strong, in quite a while.

"I don't want to know anything about who, or what it is. Although it is obviously dear to you."

"It can be used to destroy the world," Buffy said. "And the monks did send it to me."

"Of course," he said. But he didn't sound like he believed her. And he didn't take his hand off her arm.

"Severus …" she begun, not sure she had an ending.

"You're a fighter, Miss Summers. But few people, even a Slayer, would voluntarily walk into this conflict."

"Dawn's in Italy. But I never got the hang of Italian."

Severus raised his other hand to cup Buffy's cheek. She had to stop herself from closing her eyes.

"You seek death?"

"I've died twice. It doesn't scare me."

"But living without the threat does," he said. "What do you do if it's not just what keeps you alive."

Buffy did close her eyes. She didn't want to look at him anymore. His statement had been as much for himself as for her, and she was sure it would be reflected in his eyes.

The cold of the dungeons finally wormed its way through the layers of her robes with a cool caress. She shivered. Just as gently Severus put his arms around her and she was able to lean against his body. It was warm though the black linen.

She smiled, revelling in the feel of a human body so close to her own. The small cynical part of her mind she'd had enough trouble ignoring before she'd been pulled out of heaven asked how long she thought this spell would last.

Her arguments with it were cut short when he pulled away. Her eyes opened and she looked straight into his for a brief moment before he kissed her.

His lips were dry and Buffy didn't think he'd kissed anyone in sometime. But then, neither had she, and this felt so nice. She leant into him, lending him her weight. He wrapped his arms around her more firmly and she smiled. He took the opportunity to deepen the kiss.

Dragging a hand up her back, Severus tangled his fingers in her hair.

"Sev… mmm," Buffy managed to say.

She gave up trying to speak and kissed him back instead.

He broke the kiss long enough to breathe her name and draw her closer.

Buffy's brain decided that it was an opportune time to interrupt her. It told her in uncertain terms that if she didn't pull out now, things were going to happen.

Buffy told it, as best she could, that she was going to let them.