He was like the water to her magnificent fire, and in turn, she was the soothing liquid to tame and dampen his fury. They cancelled each other out, rather like toffee apples – neither of them should ever have existed. A paradox, who had fallen in love with a paradox. A Time Lord and an impossibility. A murderer and the man she had killed. The only people who truly understood each other. She knew his real name, the letters he only uttered on one single occasion in his life, the syllables he told only to his love. But he still didn't know who she was, and she wasn't going to tell him anytime soon. Jeez, it was all rather complicated, but isn't every single love story, on some basic level? True, they were travelling in opposite directions, knowing and not knowing each other, loving and not loving each other, all at different points and times, but they would make it work. No one understood why they bothered, but no one understood their love. Not even each other. They still had so many secrets…

'I'm not going to sit back and watch and allow you sacrifice yourself for me again!' he yelled in her face, yanking her closer to him, preventing her from moving towards the chair in the technological box. An expression of utmost confusion glinted away in her clear sapphire eyes. Her wonderful smile faded into the past and she hooked her eyebrow when she asked, crisply and clearly,

'"Again"?'

It had been a simple slip of the tongue; he had accidentally let it out without thinking, begging and desperately searching for a way, a reason to make her stay. He had to fix this immediately, she could never know about the Library until she went, and even then she would have to make the impossible choice by herself. By all the stars, he wished he could prevent her from having to make that choice, but she was River Song; she would kill him if he interfered at all with their timeline. It was messed up enough as it was.

Pain seared through his mind, the memories and the horrific moment where she had looked him in the eyes, her Doctor, the one man in the entire cosmos that she trusted with absolutely everything, and she was incredibly brave, and told him that he would see her again.

You, me. Time and space. You watch us run.

His eyes glinted with tears, the way hers had, mirroring her actions. The moment, the moment he had watched this incredible, sassy, and overall heart-breaking woman sacrifice herself for him, he was lost. Spoilers, she had teased. Her last words.

River Song snapped her fingers in front of his blank face. Gosh, this regeneration was a lot more emotional than the others, she pondered casually, unaware of the emotional battle raging on inside of him. She knew him, but not that well. But she could tell something was bothering him.

'Doctor!' she murmured, restraining from shouting out in anticipation, 'What do you mean by "again"?'

He breathed in, 'River Song,' he began to explain, mourning rising in his voice, making the words tremble and shake as they were exposed to her ears, 'one day, you're going to be very brave for me…'

'Isn't it like that every day?' she joked, throwing her head of curls back and laughing loudly. She did not notice the tear slip from his right eye and fall to the ground in sadness.

'River, please listen,' he whispered, holding both of her hands, and rubbing them soothingly within his own. She bowed her head in apology and brought her face back upwards, her expression now worried and anxious. Okay, he was being very calm and polite, something must be wrong, 'One day, you're going to have to be especially brave. You're going to make a decision that will change everything. I, of course, won't approve, but you don't need my approval. You're going to be extraordinary.'

'Well, that I already am,' she muttered to him, not even being the slightest bit untruthful. He smiled, typical River.

'Yes, Doctor Song, you truly are,' he whispered, not noticing that he was leaning forwards towards her, their noses touching gently against one another's. He put both his hands on her shoulder, comfortingly and warmly, and she, for one single second, doubted that he knew what he was doing. She closed her eyes contentedly and leaned in towards him. Suddenly, she felt herself being spun around and she opened her eyes, annoyed.

He had quickly avoided her lips and ran over to the Pandorica and was beginning to strap himself in. She rushed over and yanked at the metal straps, trying to grab his sonic screwdriver, hanging out of his mouth as he did up the chains. She fumbled desperately, not once looking at him, tugging with all her might at them. He smiled. She did care.

He allowed her to release his left wrist, but not anything else. She stared up at him, tears glistening in her eyes, trawling down her cheeks.

'Please, please…' she begged quietly, 'Please Doctor. Please.'

Her cries almost broke his hearts. Screw that, they ripped them apart. Using his free left arm, he clutched at her waist, so near to where he was sat, and pulled her onto his lap. As soon as she was sat on him, she shot out her arms and wrapped them around his neck, and sobbed into his chest. He rubbed her back soothingly, shushing her gently. The tears cascaded like he had never seen, not from anyone. He hadn't thought that was he was about to do would affect her so badly.

'River Song,' he began, fumbling with her curls, 'you know I have to do this.'

'But you can't' she sobbed, choking on her words, clutching him even tighter like a little girl would to her teddy bear, 'You don't understand, I can't lose you.' she resisted the temptation to say "again".

He pulled her away from his chest, placed his left hand on her cheek and whispered, 'Don't worry, you'll see me again. I've still got everything to come.'

And slowly, in the midst of the collapsing stars and universes, The Doctor, destroyer of worlds, and River Song, archaeologist and trigger-happy woman galore, shared their first kiss, regret burrowing in the back of their minds. This might be the last time. She pressed her lips furiously against his, and he responded in a way she hadn't thought possible so early on in his time stream. He hugged her, his loose hand on the back, the other dying to be released to run through her curls and stay firmly at her waist.

But it was all over too soon. She pulled away, and whispered, in the words he had taught her, I love you, in Gallifreyan. He mumbled back the same words, and a smile she didn't believe she could muster up appeared on her face,

'I'll see you again Miss Song. Don't forget me.' He said in her ear. He pulled the sonic screwdriver out of his top pocket and placed it in hers. Her eyes widened in shock and she motioned to give it back, but his eyes and mind seemed to say You need it more than I do. Remember me, always remember me. He kissed her one last time and then went cavorting off into the sky, yelling GERONIMO and thinking of her.

And so, whilst the rest of the universe carried on, not knowing who "The Doctor" was, River Song remembered. In all honesty, how could she possible forget him?