So this story came about as a prompt from mychakk who wanted a story about Sherlock and Molly making a pact to have sex when they were younger. I hope I have done the prompt justice. So mychakk this is dedicated to you!

It will be a tale of two halves, literally and figuratively. Two chapters but also it flicks between modern day and Molly's memories from 15 through to 18. I didn't want big chunks of the story italicised so I hope it is obvious where the times change.

I still own none of the characters but am eternally grateful that I am able to play with them.

Chapter 1

Today was Molly's 33rd birthday and bar a phone call from her mum and a joint card from her colleagues at work there was no one who really cared. Molly sat down heavily on the settee with a glass of wine and pondered where it had all gone wrong. She had hoped to be married by now, to have kids or at least have plans to have kids. Instead all she had was her job and a small, ginger cat.

She sipped on her drink and found herself remembering back to when she was fifteen, it seemed like a lifetime ago. She had been awkward, quiet and shy, the class swot; she had never really had many friends which was why it was strange that her best friend was her complete opposite. He was rebellious, quick witted with a cutting tongue but above all he was a genius. A straight A student already earmarked for Cambridge or Oxford, which was why he got away with playing truant from school so much.

Back then he was known by his first name, William, or Will as he preferred to be called. He just seemed to latch onto Molly. More often than not when she left the library, having finished off whatever homework she'd been set, he would be waiting for her; leaning on the library wall smoking a cigarette or drinking a bottle of beer.

He'd walk her back to her place and, given her dad's long hours working as a plumber and her mum's complete indifference, they'd go up to Molly's room and listen to music or chat about anything that took their interest. Unlike most teenage chat it was normally science based or medical. Molly was already keen on becoming a doctor and Will was thinking, on the advice of his parents, about pursuing a career in Chemistry though he was ambivalent at best.

It only took Molly one week into this weird friendship to fall madly in love with Will. At first she hoped and prayed he would ask her out but as the weeks progressed into months she began to realise that would never happen. He didn't just show no interest in her he showed no interest in anyone, not sexually.

It was about eight months into their friendship and just before her sixteenth birthday when IT happened.

It was a warm summer's day and Molly had been enjoying sitting on a rug in the park doing her homework when the other girls had found her. They were all from Molly's class, all popular, all with older boyfriends, normally from the year above at school. They regularly mocked Molly for being mousy, ugly, geeky and today was no different. They laughed at her, at her clothes, at the fact she'd never had a boyfriend and most likely never would. She'd grow old and alone and die with hundreds of cats, that one set them off into helpless giggles.

They all knew about her friendship with Will but they also knew he'd never shown her any interest. With hindsight Molly realised they were probably jealous of her friendship with him, he was the best looking guy in the whole school. They'd all made a play for him at one time or another and been knocked back, some more cruelly than others, but at the time Molly didn't see this she just took their barbs and laughter and tried not to let them see her cry.

They walked away as Will appeared on the other side of the park heading towards where Molly was sat. He threw himself down on the rug and started to light a fag.

'Hi, how are you?' He suddenly noticed her distress and sat up straighter his eyes narrowing, 'Hey, what's up? No hang on don't tell me I want to see if I can work it out.'

Molly rolled her eyes, this was Will's new game. Trying to work out things about people from subtle clues. He had been rubbish at first but Molly had to admit his guesses were getting more accurate nowadays.

He sat and looked her up and down, he took in her slightly red rimmed eyes, the girls from their school sitting not that far always casting occasional glances over at them before giggling and gossiping to each other.

'What did they say to you Molly?' He scowled in their direction but was just rewarded with more giggles.

'Nothing, it doesn't matter.'

'Yes it does. Come on tell me. We're mates aren't we?'

'It was nothing that wasn't true, they just didn't really have to rub it in.'

'Just tell me, I'm getting bored here.'

Molly sighed, knowing how quick Will was to boredom, 'they were just laughing at the fact that I've never been kissed, that I haven't got a boyfriend and I haven't had sex.'

She stared at him sullenly as though daring him to contradict it, 'see nothing that isn't true, I mean look at me Will, I don't look like them, I don't dress like them. Who's ever going to want me?'

Will frowned again, he hated emotions and feelings, they were too complicated and messy. 'Oh just ignore them. I've not had sex either and neither have most of them, they just pretend they've done it so they look good in front of their mates.'

'Yeah, well. At least they'll get a chance to have sex. I'll probably die a virgin.' Molly was in a full on sulk by now and it made Will laugh.

'I tell you what then Molly. If you haven't had sex by the time you're 18 I'll sleep with you. That way we can both go off to Uni as non-virgins.'

'Haha very funny Will. Are you taking the mickey of me as well? I thought you were my friend.'

'I am and I mean it. Tell you what, I'll prove my commitment to the promise. Close your eyes.'

'I'm sorry...what!'

'Come on Molls, close your eyes.'

Molly sighed once more but did as he asked. A quick glance told Will they were still being observed so he leant forward and catching the back of Molly's head he pulled her too him and kissed her.

Molly hadn't been expecting this at all. She felt Will pull her towards him and then his lips were on hers. His mouth was warm and he tasted of cigarettes but his lips were soft as they moved against hers. She thought her heart was going to explode, she felt dizzy and knew she was holding onto his t shirt for dear life.

It only lasted a minute or so but it wasn't long enough for Molly. When he pulled back she opened her eyes feeling dazed and unsure. Will was smirking at her and saying something, 'there you go Molls, a kiss to seal my promise and proof for those cows sitting over there that you have been kissed. They'll also assume I am your boyfriend now so that's two birds killed with one stone. Anyway enough of this my dog, Redbeard, has an abscess, it's so cool. Maybe we could get some puss from it and use one of the school microscopes to analyse it whaddya think?'

Molly nodded her head in agreement and listened to Will prattling on about the different experiments they could conduct but her head was firmly fixated on that kiss. Her first kiss. It just made her want more, want him more.

He never mentioned it again and six months later he and his family moved away. Apparently his brother Mike was finishing university and had got a job in London, in the civil service or something. Anyway given that Will was expected to go to Oxford in a couple of years his parents had decided to move to a village in between London and Oxford so they could all keep in touch better.

Molly had cried for a week after he had gone, not just because she had fancied him but because he was her friend, almost her only friend.

They'd kept in touch initially, although it was quite sporadic from Will. He'd send her interesting articles that he'd found or photographs, often of dead animals, that he'd come across, describing his he'd figured out their cause of death. His morbid interests made her smile, which was probably why they'd become friends in the first place.

After a year though it had pretty much dried up. This had not been a world connected by computers and social media, they'd only had telephones and letters to keep them connected. Molly had kept every single note and article and photo in a box under her bed.

On her eighteenth birthday she'd fleetingly wondered if she would hear from him, if he would keep his promise (after all she was still a virgin) but she'd heard nothing.

A week later her parents went on holiday for the first time in five years. Molly hadn't wanted to go with them, it had sounded really dull, so she was home alone and looking forward to maybe having some friends round for a girly chat and a sleepover.

The first night her two best friends Meena and Sarah had come over bringing with them a cheap bottle of cider. They'd found some glasses and sat around drinking and playing truth or dare, though the truths weren't very risqué and the dares were a bit tame. It was fun never the less and ended up deteriorating into a general chat about the boys in school they fancied and their chances or not of going out with them. Molly was surprised then when the doorbell rang just before ten o'clock.

She opened it to find Will stood on her doorstep holding up a twelve pack of Durex, 'hey Molly, you didn't think I'd forget did you?'

Molly stood there in shock for a moment before she realised a teenage guy was stood outside her parent's house holding up condoms, 'Oh my God, get inside before the neighbours see you, they do know my mum and dad you know!' She pulled his arm down that was holding the box and used it to pull him through the door.

'What the hell are you doing here?'

Will's face fell, 'well I had hoped for a more enthusiastic response. I travelled a long way to get here.'

Molly looked past him at the slightly beat up motorbike that was parked where her parent's car normally sat, 'is that yours?'

Will looked proud, 'yup. My parents got it for me as a bribe to make sure I passed the Oxford entry exams. I'm off to Balliol College in October to study Chemistry, well for as long as I can stand it anyway. You?'

Molly smiled, 'York, I'm doing medicine.'

'Doctor Molly Hooper, it has a nice ring to it.'

'I can't believe you're actually here. I missed you.' Molly tentatively moved forward and put her arms around him. It took a moment but he slowly brought his arms up to hug her back briefly. 'Come and meet my friends...do you want a drink?'

'God do I have to, can't you just get rid of them.'

'No I can't. Come on...please.'

He grumpily followed behind her and sullenly sat on the settee drinking the insipid cider until her friends got the hint and left. They remembered all about Will and Molly's massive crush on him, they weren't about to rain on her parade by forcing her to go through with their sleepover. They gathered up their things and made their way out giggling their goodbyes to Will and mouthing Good Luck to Molly. At the door they made her promise to ring them as soon as he'd gone to let them know EVERYTHING.

Molly shushed them, 'he can hear you know,' but promised none the less.

By the time she got back to the front room Will had found her father's whisky and poured them two glasses. 'Here you go, you shouldn't drink cheap booze Molly it's disgusting.'

'And you shouldn't drink my dads whisky, it's expensive. How on earth am I going to replace it?'

'Oh don't stress, I'll get you another bottle if you need it. Now come on drink, we need to be more relaxed if we're going to have sex.'

Molly literally choked on her drink, to the point that Will wondered if he'd have to hit her on her back. 'You can't be serious about that. It was years ago when we made that promise, we were just kids.'

'So. You're still a virgin, I'm still virgin. I know you like me so the question is more why not?'

Molly sat sipping the whisky trying to think of a good reason why not. She liked him, she really liked him, she always had and the thought of losing her virginity with him felt safe and comfortable. Plus chances were this would be the last time she'd ever see him. It was unlikely their paths would cross in the future. She didn't want to look back on this as a lost opportunity, a regret. It also helped that the whisky was making her feel warm and fuzzy.

'OK.'

'Great,' he immediately put his empty glass down and came and sat on the floor opposite her. Molly gulped nervously, biting her lip.

Slowly he put up his hand and used his finger to pull her lip out from between her teeth. She watched him as he did, noticing his pupils were dilated, his breathing seemed as erratic as hers. It helped knowing that he was as nervous as she was, it gave her the confidence to move forward and hold his face before kissing him.

Am I mean ending it there? I hope you're all enjoying it so far. The final half will be posted in a couple of days so until then fill your time with reviews and follows and favourites. Go on you know you want to.