River breathed in the cinnamon scented air; this was by far the most romantic place the Doctor had ever taken her. Asgard was spectacular, and there were no aliens causing trouble, which was a bonus. As much as she loved spending time with the Doctor, it was nice to have a relaxing evening instead of spending her time chasing after deadly aliens.
The Doctor was staring at her again, and though she enjoyed the attention, it had started to become disconcerting.
Turning to look at him she asked "Doctor, what's wrong?" "Nothing" he replied in a rough voice. He sounded drained.
The picnic had consisted of all her favourite foods, well almost all of them, there was a distinct lack of apples, and some of his, which explained the fish fingers and custard that stood on the centre of the rug. They sat on top of a hill overlooking an amazing landscape, the shining city and golden trees glinted in the sunset.
The Doctor moved some food away from him and lay down with his head on her lap, gazing tiredly at the orange sky. He wasn't prone to romantic acts, so this took her completely by surprise, and his whisper of "I love you" was even less expected. But she knew he wouldn't tell her what was wrong. If he was going to, he would have responded to her question.
It had been a spectacular day exploring the shining city, and this sunset was breath-taking. But the Doctor was sad. And she could think of no reason for this other than her future. His past.
She knew his future and he knew hers. Two timelines constantly twined. She knew all of the trials he would face and all of the kisses they would share. As she got to know him better, he came to know her less.
At the beginning she forgot this, but after the wedding she never would.
The Doctor sat up and kissed her passionately. She was taken by surprise, but she kissed him back, longingly.
He picked her up and carried her into the TARDIS towards her bedroom, where he lay her on the bed, and closed the door.