I thought I'd give a professor/student AU a shot :D Now, this was originally intended to be a oneshot but after having written over 3000 words I realized I hadn't even done half of the story, so I decided to make it a 3-parter. Here comes part 1:

Gold & Silver Line My Heart

OOO

Clara had thought going back to university was the right choice even though she was in her late 20s. Other people did it all the time. In fact her classes were swarming with people of all ages, even a few pensioners. She wasn't exactly sure what she would do after getting her degree in sociology but she had only just started and there was still time to figure everything out. What Clara knew for certain was that she couldn't ever go back to teaching.

It had been exactly one year since her boyfriend and colleague had died in a car accident and after a break she had tried to go back to school but everything about that place had reminded her of him. Clara had realized it might be better to switch schools after she had broken out in tears three days in a row in front of her class but it was no use. She had still expected Danny to knock and stick his head through her classroom door any minute and it just couldn't go on like that. After speaking to her family and even a therapist she had come to the conclusion that a change of careers might be best.

That was how Clara, now two months into her first semester, found herself attending a class on gender studies. She had gotten the results of her first essay this morning, an A+, the same grade everyone else seemed to have received as well, which was odd. She hadn't exactly given it her best and even the others seemed baffled.

She turned her attention back to Professor Doctor John Smith, who was, as she had learned an expert on the subject. Yet her mind kept wandering. Today was the anniversary of Danny's death and she would've stayed home, pretending to be sick, if Smith's class hadn't been obligatory. She usually loved attending his classes but it seemed as if her professor wasn't having the best of days either. Maybe he had overslept, he certainly looked like it. Hair ruffled, unshaven, his rimmed glasses slightly askew and she could've sworn that he was wearing the same clothes as yesterday. He also seemed very scattered, changing the subject every few minutes, leaving sentences unfinished and half an hour before the time was up he told them to go home.

Clara gathered her things and started to approach his desk.

"Uhm, Professor Smith?" she asked carefully.

He looked at her over the rim of his glasses, confused. It took him quite a while to reply. "You're new. First semester?"

"Yeah. Listen, about my essay. . ."

"Explains why you don't know my nickname. Most students just call me the Doctor," he gave her a half-hearted smile as he continued to stuff his papers into his briefcase.

"Oh, okay. I have a question about my essay. Are you sure you've given me the right grade?" Clara held her paper into his direction, her eyebrows raised.

"Yes, yes, quite sure. Look, can this wait until tomorrow?" the Doctor stood up straight and looked at her.

Clara felt slightly intimidated by his posture an the tone in his gravelly voice.

"Yeah, sure," she replied.

"Now, if you'll excuse me," the Doctor grabbed his briefcase and headed out of the room.

OOO

The library had been Clara's safe haven from the first day on. It was where she could retreat to when she felt close to tears and bury her nose in a book. Only today her haven appeared to be more of a fridge. The heating was out, which wouldn't have bothered her hadn't it been November. After spending several hours freezing despite her warm coat and not getting any work done, she decided it might be better to go home and warm up before she caught a cold.

As she walked through the streets, shivering in the snow, she passed a small pub in a back road that she hadn't really taken notice of before. A hot cup of tea or coffee would be really nice now, she thought. Clara spun around on her heels and entered the pub, a wave of hot air blowing into her face. She still kept her coat on and approached the bar when she suddenly spotted her professor sitting on one of the bar stools in front of a glass of what looked like strong alcohol. At least she wasn't the only one having a bad day.

Clara considered leaving or finding a spot in the darkest corner of the pub so he wouldn't notice her but it was too late for that. Professor Doctor Smith, or the Doctor, had already seen her and was now waving at her to come closer. She approached him carefully.

"Miss. . . Oswald?" he asked uncertainly, his voice even raspier now.

Clara nodded.

"Listen, I'm sorry about earlier," the Doctor said with a slight smile, clutching his drink in both hands, "Your grade is fine. Don't worry about it."

She wasn't sure what to reply. Should she thank him for giving her a grade she obviously didn't deserve? Sit down? Leave?

"In fact, I gave everyone an A+. Couldn't be bothered with grading last night. Take it as a matriculation present."

"Uhm, thanks," Clara said hesitantly. He looked absolutely miserable. Should she ask him if he was okay? Other people's problems always seemed to distract her from her own, "Are you all right?"

The Doctor looked up from his glass and stared at her for a moment. The he proceeded to take of his glasses and rub his eyes as if tired.

"Do you want me to leave?" Clara asked. She wasn't really comfortable in this situation. The Doctor was such a strong presence, it intimidated her.

"No, no," he shook his head, "Why don't you sit down?"

Clara unbuttoned her coat reluctantly and took the seat next to him, praying for a bartender to show up soon and save her from awkwardly sitting at the bar with nothing to hold on to.

"Do you want something to drink?" the Doctor asked her and she noticed his gaze wander over her figure. She nervously fiddled to close her coat again.

"Tea would be nice. I'm freezing," she admitted.

The Doctor snorted and took a sip of his drink. "Scotch does a better job at warming you up, trust me. It's also very useful if you're having a really, really bad day."

"Okay, I'll have one of those then."

He waved at the waiter who immediately refilled his glass and also brought one for Clara. She took a sip carefully and made a grimace as the alcohol burned in her throat. But the Doctor was right, it was warming her up instantly.

"So, what screwed up your day?" he asked after a while.

Clara shrugged. She didn't really feel like talking about Danny. In fact, she had told no one at university so far, not even the two friends she had made. She was so sick of their stares, of everyone feeling sorry for her. She thought that maybe if no one knew about Danny and treated her like they would any other person she could get over it and forget.

"Just the usual," Clara lied, downing the rest of the scotch, "Just feeling down lately. And you?"

The Doctor called for the bartender again to refill their glasses and reached inside his briefcase, pulling out yesterday's newspaper. He opened it at the birth announcements and Clara spotted a picture of a pretty, young woman, not much older than herself, holding a tiny newborn.

"That is my ex-girlfriend Eileen. She left me a year ago because I wanted to get married and have children and she didn't. At least that's what she said," the Doctor explained, avoiding to look at the picture.

Clara started to read the article.

"We congratulate Eileen Simmons and her husband Mark to the birth or their son Danny."

Danny. The name stung but Clara was determined not to show it. Instead she read the announcement again.

"Wow, that really sucks," Clara uttered.

"Yep. But now I know it wasn't marriage that scared her away or having kids, it was me. I guess I earned it. Somehow," the Doctor raised his glass to his lips again.

"Why? What makes you say that?" Clara was honestly curious now.

"I have . . . a reputation. Of which you wouldn't know because you're new, but. . . I have. I have slept with a female student more than just once."

Clara gulped. It really wasn't what she had expected, not of him. He had always seemed such a professional during class.

"I, uhm, I didn't push it. I'm not a creep if that's what you're thinking now," he threw her a glance to check whether she seemed disgusted or not, "I always waited for them to make the first move. Most just did it because they wanted a better grade. I knew that, but I didn't care. Eileen was different though. I loved her. We had been together for two years when I proposed. A few months later she left me, for him," he pointed at the newspaper, "apparently."

"I'm sorry to hear that. It's really not a nice thing to do to someone. She could've told you the truth at least," Clara finished her glass. She wasn't used to this kind of strong liquor and she was starting to feel a little light-headed.

"I learned my lesson," the Doctor concluded, "Hands off the students."

"Oh, I'm sure not everyone is like your ex. You'll meet someone," Clara nudged him gently and smiled.

The Doctor turned his head towards her and a smirk formed on his lips. "You're very kind, Clara Oswald," he sighed, "But for now I think I'm gonna get drunk, pass out on my bed and be completely hungover in class tomorrow. What do you say, one more drink and I'll stop bothering you with my boring life?"

Clara knew she should say no. She should decline and demanded a cup of tea instead, but the Doctor was right. The scotch had really warmed her up and the thoughts of Danny seemed further away then ever. And here was her nice professor in desperate need of some company. So she agreed.

OOO

Clara woke up, her head throbbing with the pain of the worst hangover of her life. She opened her eyes for just a second and closed them again quickly, the light blinding painfully. She dragged the duvet over her head and just wanted to fall back asleep, but something didn't feel quite right. This wasn't her bedding. Hers was fluffy and warm and the one she was wrapped in felt smooth and slightly cooling. Despite the pain she threw away the duvet and opened her eyes. In panic she realized that she wasn't in her bedroom, she wasn't even in her own apartment. She stared around the scarcely furnished, completely unfamiliar room. There was the bed she was lying in, a small closet and a rug. Where was she? Clara frantically searched her brain for an answer, but the previous night was nothing but a huge, black hole. She had gone to her classes the day before, to the library and then to a pub, where she had met. . . oh God.

She must be in her professor's apartment, or rather loft, by the looks of it, with no recollection of how she had gotten here or what might have happened afterwards. She was afraid to check under the duvet, but she could feel the bedding on her skin and knew she was naked. Clara buried her head in her hands. What had she done?

She scanned the room for any piece of clothing and luckily found her knickers. She got out of bed and quickly put them on, but the rest of her clothes weren't here. All she could find was her professor's shirt from last night. With no other choice than to walk around naked, she slipped it on and carefully opened the sliding door to what seemed to be the living room.

Clara crossed it carefully, trying not to make any noise when she found herself in front of another sliding door. She didn't know what to do so she knocked.

The Doctor opened the door carefully and she considered herself lucky he was already dressed.

"Sorry, I didn't know if I should wake you or not. Hope you didn't miss any classes," he said apologetically and gestured for her to come into the kitchen, "I made coffee, if you want some. Ham and eggs are almost done as well."

Clara walked into the room and sank down on the nearest chair. "What time is it?"

"Almost 10," he replied, busying himself with rearranging the plates.

"No," Clara sighed, sniffing the coffee. The thought of eating or drinking made her stomach turn over.

"No what?"

"No, I don't have classes. Yours is the first today," she said and the horrifying thought crossed her mind that she would have to sit in his class and look at him very soon. She would feel so awkward that the whole world would see what had happened between them last night. Whatever had happened.

"Doctor," she began reluctantly, biting her lip, "What exactly happened. . . last night?"

He turned around to look at her but Clara didn't dare look back. She saw him just out of the corner of her eye. He had obviously been awake for a while, showered, shaved and put on some other clothes, which was convenient. She was wearing his old shirt.

"You don't remember?" he raised an eyebrow.

Clara tried to think back again, the coffee somehow rebooting her brain.

They had been at the pub, drinking scotch and it had only taken her a few glasses until she was drunk. He had offered to walk her home then, passing his flat. It had seemed like a good idea back then to go inside cause neither of them had really felt like walking all the way to her apartment. He had produced a bottle of tequila from his kitchen cupboard, still determined to drown his sorrows. She might have had a shot or two as well, maybe more. Probably more. At least it would explain why she couldn't recall anything after that.

"I remember the tequila," Clara confessed.

"And?"

"And nothing. Woke up in your bed," she shrugged, the sudden movement hurting her head again.

"I'm trying very hard not to take this personally," the Doctor chuckled.

"Well, enlighten me. What happened?" Clara demanded although it was obvious.

The Doctor turned around to switch off the stove and walked over to the other side of the small table, taking a seat.

"You're right. We had a couple of tequila shots, which was probably a bad idea. I put on some music, we danced."

Dancing seemed to ring a bell in Clara's mind. She could recall a bit of that now. It had been some oldie from the 70s and he had twirled her around, their hands and bodies touching each other in ways not really appropriate for a professor and his student.

"We kissed and then we had sex," the Doctor concluded, "It's a shame you don't remember, really. It was good."

"Oh God," Clara muttered, hiding her face behind her hands, "Oh God. Oh God, oh God, oh God."

"Is everything alright?" the Doctor leaned a little closer, sounding worried.

"It was stupid. This isn't how it was supposed to be. Two months into university again and I've already slept with one of my professors. This is bad," she said desperately.

"Clara, we're both two adults. Sure, it wasn't the wisest thing to do, but we've had a crappy day, I felt lonely, and you probably, too. This doesn't have to be a bad thing, it's only as bad as we make it," he said gently, taking her hand into his.

Clara exhaled sharply. "Yeah, I guess you're right."

"Do you want some breakfast?" he asked, "I'm afraid I have to leave soon but you can use the shower before you leave if you want to. I put your clothes in the bathroom."

"Thank you, but I'll be late for your class if I take the time to shower."

"Don't worry about it. You're not feeling well and it's sort of my fault. I'll mark you down as attending."

"Thanks," she said, her voice weak.

The Doctor pushed a plate filled with delicious looking ham and eggs in front of her nose and Clara felt her appetite returning at the sight of it. They had breakfast in silence before the Doctor announced he had to leave for work.

"You can take a shower or go back to bed if you want. Just close the door behind you if you leave," the Doctor reminded her.

If you leave. He almost sounded as if he expected her to still be here when he returned after classes and Clara most certainly wouldn't let it come to that. She nodded and got up to say goodbye, hearing him take a deep breath.

"Listen, even if you don't remember. I had a really great time last night, I haven't felt that good in months and I just wanted to thank you for that," he said earnestly and bent down to give her a swift kiss on the cheek.

Clara watched him turn away from her and grab his briefcase. Now was her last chance to say it, even if the truth hurt. As far as she could remember she hadn't been thinking about Danny all night.

"I had a great time, too. I think," she mustered up a smile and waited until he was out of the door before she started crying mercilessly.

She had cheated on Danny with her professor. Of course he was dead but Clara felt as if she had betrayed their love and insulted his memory.

You can't mourn him forever, you need to go out into the world and live your life, her grandmother had told her a few months earlier and that was when Clara had decided to go back to university. But her gran was doing the exact opposite. Her grandfather had died years ago and she had kept their apartment a shrine in his memory. Clara felt as if she ought to do the same, after all, her grandmother was the woman she had always admired the most.

Clara took a deep breath. She needed to get out of here and she would do exactly what the Doctor had said. Shower and go back to her own apartment. She would pretend that last night had never happened and after the semester was over she would never have to see Professor Doctor John Smith ever again.