A couple of hours and a pizza delivery later, their game was concluded and both were busy with their own thoughts, although Sheldon at least was apparently engrossed in The Empire Strikes Back. Incidentally, Amy had won. Almost as if the team captain had something on his mind that evening…Ten o'clock came, and they both spoke at the same time.

'Well, I guess we ought to…' Amy began, as Sheldon said much the same. 'Shall I get my stuff?' she asked then, almost shyly. He left for his room as Amy pulled out her neuroscience bag of tricks, and sat tentatively on the edge of the couch, waiting to be asked to come in. When Sheldon called, she found him already lying in bed, covers pulled up tightly as if for protection, a last ditch bastion of propriety.

'So how was it last time?' Amy asked. 'Sleeping with all this on?'

'Well, I can't say it was comfortable, but such sacrifices must be made for the pursuit of Science,' Sheldon replied, trying to sound as detached as ever, but watching every move she made with a growing, fascinated intensity that was hard to hide.

'Indeed. In the past, many made sacrifices far worse,' Amy agreed, trying not to notice. She lingered over his hair, fingers gentle as she attached the sensors once again. Tonight, they'd just brushed the back of his neck, rather than his ear, and in spite of the hot summer's night, Sheldon couldn't help but shiver at her touch. She felt it, and abruptly drew her hand back, burning inside. She knew she had to go – now – or she'd lose all resolve and reason. Right now, that was a chance she couldn't afford to take. It was part of the journey they'd started, without even knowing it, a long time ago, but this was an unpredictable, uncertain stage of it that had to be handled with care.

'OK, you're done,' Amy said, unconsciously smoothing her skirt and tugging at non-existent creases on her new shirt. She hadn't taken it off from the moment Sheldon gave it to her. 'Wow, it's later than I thought! I really ought to get going…'

'Oh.' The last thing Sheldon wanted was for her to go. 'You know you could stay? You said you might last time?'

'I know…but…not tonight.' Amy looked up at him just then and caught the look in his eyes that said what he didn't. The one that said he wanted her.

'OK,' Sheldon conceded, reluctantly looking away. 'You're right, it's late. Goodnight Amy.'

'Goodnight Sheldon,' Amy replied, her hand on the door. 'You know, you could always come bowling with me tomorrow? See me kick those hippy butts?'

He smiled one of the rare, genuine smiles then that Amy suspected were only for her. 'You bet I will! With my coaching, how can you lose?'

'Great! I'll see you tomorrow!' Amy smiled in return, grateful for the turn in conversation, and bid her farewells. As soon as she left, Sheldon let out the breath he'd been holding, and thought of the curves of her body under his hand and under that shirt.

'…and so, Commander Cooper, she's a young Vulcan Ensign just out of Starfleet. This is to be her first command, and as such, has requested further study of comparative Cosmology,' continued Captain James T Kirk, 'and I want you to provide any lessons she may need.' Did the Captain wink at him just then?

Nonetheless, Sheldon readily agreed. Comparative Cosmology with a junior Vulcan Science officer sounded a fascinating assignment, and he was keen to meet his new student. Suddenly, he was alone, and then, the door to his quarters slid open with a soft hiss, and there she was. Vulcan Amy – with slightly darker hair and pointy ears, dressed in the regulation Starfleet uniform of little skirt and knee boots, just as he remembered.

'Commander Cooper?' she asked, coming to sit before him, a challenging look in her eyes. 'I understand you have a programme of study prepared for me?'

'Yes, Ensign. I want to begin with the definition of the various types of Cosmology, beginning with the variant known as Physical Cosmology, which is the branch of physics and astrophysics that deals with the study of the physical origins and evolution of the Universe…'

He paused. The young Vulcan woman looked distracted and somewhat arrogant as she stared back at him, legs crossed, her skirt high up her thigh.

'Indeed. Continue, please.'

'Modern scientific cosmology is usually considered to have begun in 1917 with Albert Einstein's publication of his final modification of general relativity in the paper 'Cosmological Considerations of the General Theory of Relativity.' General relativity prompted cosmogonists such as Willem de Sitter, Karl Schwarzschild and Arthur Eddington to explore the astronomical consequences of the theory, which enhanced the growing ability of astronomers to study very distant objects. Prior to this (and for some time afterwards), physicists assumed that the Universe was static and unchanging.'

'Interesting,' she said, her eyes flicking up at him, 'but irrelevant.'

'Irrelevant? Exactly what do you mean by that, Ensign?

'I appear to unable to concentrate at the present time, Commander, so anything you say is irrelevant. My lack of concentration is likely to be a result of the onset of Pon Farr, and you appear to be a suitable mate,' she continued, walking around his desk and sitting immediately in front of him. 'I take it you are aware of the condition?'

'I am, but you appear to need a reminder of the chain of command,' Sheldon replied. 'I understood you to be my student. As such, you follow my rules.'

'Is that so?' Vulcan Amy asked, sliding off the desk and onto his lap, wrapping her thighs around his waist. 'Why don't you prove it?'

'Then get over there,' Commander Cooper ordered, indicating the bed across the room. A delectable look of desire mixed with defiance lit her eyes, and her skirt swished over her rear as she turned, before striding over and collapsing on his bed, her boot clad legs still crossed, looking back at him. Suddenly he was with her, over her, hands running over her uniform and under her skirt. She cried out, wrapping her legs tightly around his waist, pushing herself into him hard. She pushed him back slightly then, and sat up. Never breaking eye contact, she reached round to the back of her dress, and slowly drew the zip down. He leaned forward and pulled the sleeves from her shoulders, and she wriggled the rest of her body free, baring petite, perky breasts to the air.

He'd seen them before, warm and wet, small soapsuds alternately soaking into her skin and dripping from her. Last time, he couldn't touch. This time, there was no hesitation, and she cried his name as he took them, caressed them, while her hand snaked down…

And then she was gone. This time, his sheets and pyjamas were dry, but the desire she'd provoked was uncomfortable, hard, undeniable and obvious. He woke, and lay there, hot and sweating, unable to do anything about it. He caught sight of the blinking red light of the camera, and felt guilty under its gaze. Waiting for such 'incidents' to stop was not unusual for him, and he'd even prided himself on his ability to do it efficiently and without resort to…what lesser men did…but it was so hard to deny it tonight, and he couldn't wait to see her again.

In the end, Sheldon slept, although it took some effort to focus on normal concerns that morning, not helped by the fact that Amy came to collect her equipment dressed in a pretty floral sundress with only the lightest of cardigans. The skirt was looser than usual, and while this should have somewhat less enticing, the way it moved as she walked was every bit as fascinating. In an attempt to distract himself, Sheldon opened his laptop and sent the email he'd written to Stephen Hawking, hoping the content would help the world renowned Physicist forget a certain drunk dialling incident. Then he followed up on an idea he remembered discussing with Amy some time ago, first texting Howard for the appropriate number.

'Hello, Mr Rostenkowski?' he asked. 'It's Sheldon Cooper, Howard's friend.' Funny how that seemed easier to say now. It must be down to that trip to Texas.

'Hello Sheldon,' Mike sounded somewhat surprised. 'How you doing? Howard said you'd been having a rough time recently, and Bernadette was after borrowing my service revolver to hunt you down – what happened?'

'It's a long story. I had some career issues, and I'm still working them out. There's other stuff too, but I won't go into that now. I'm calling because Howard said you'd started giving driving lessons?'

'Yeah, what, you want lessons?' Mike asked. 'Reckon I could do you Friends and Family discount?'

'Yes sir,' Sheldon replied. He was still nervous at the prospect, but Amy would be so impressed. All their friends would be …even if he had to endure the inevitable teasing from the guys to begin with.

'OK, great.' Mike paused for a while. 'When's good for you?'

'Well, I've got the summer off work now, so maybe tomorrow?'

'Sure. See you then.' Mike took his address and number, and Sheldon booked his first driving lesson in 17 years, feeling pretty good. He wouldn't be stuck in a confined, possibly unhygienic space with a stranger for hours on end, and trusted Mike. They'd got on well at Mrs Wolowitz's, and it would be good to talk again. Maybe he could offer some career advice.

It certainly wasn't a typical Friday. First driving lessons, and now not only was Vintage Video Games Night to be held at 4B this week; Sheldon wasn't going to be there.

'Hey, it'll be weird without you, buddy,' Leonard said when he'd come to pick up some games for them later that day.

'Weird for you? Imagine how it must feel for me,' Sheldon replied, not quite able to suppress the slight flash of anxiety that came from such flagrant disregard of routine.

Leonard smiled. 'You just have a good evening with Amy, OK? And wish her the best of luck from us, too.'

'She doesn't need luck,' Sheldon said proudly. 'I taught her!' He wasn't going to tell Leonard about his driving just yet - he'd rather they didn't know until he was at least reasonable.

'Hey, what you playing?' he asked then, catching sight of Leonard's games.