"Every sun will supernova at every moment in history," the Doctor screamed, as they locked him in his perfect cell. 1894 years later, Amelia Pond sat in her lonely house, with its spooky overgrown garden, and asked Santa to help her with the Crack in her wall. Her parents were gone but she didn't know it. The ducks in the pond were never there. The TARDIS came, and gave her something better than Santa, or a cop, or anybody you could ask for.
She painted stars in the sky, like Vincent once did, and it scared the grownups, because there's no such thing as stars anymore. There never were. The universe was dark, all the time, it always had been, and nobody but Amelia remembered different. They took her outside, to show her the black sky, and she kept her mouth shut. She didn't bite them, not that time.
"I just don't want her growing up and joining one of those Star Cults. I don't trust that Richard Dawkins," one of them said downstairs, and then a mysterious and jaunty figure tossed a museum flyer through the mailslot: An exhibition of the Pandorica, the strange thing they'd discovered under Stonehenge, with a red pen's flourish pointing at the façade: Come along, Pond.
So she did. She dragged Aunt Sharon through the whole National Museum, past all kinds of science and history, soda in her hand, yelling Scottishly until she found some old stone Daleks, and then again into the Pandorica room. Aunt Sharon left far behind, as she smiled up at it. A jaunty trickster snatched her soda right out of her hand, and before she could see him she found a note on the Pandorica, at a perfect Amelia-height: Stick around, Pond.
So she did. I guess eventually Aunt Sharon got bored looking for her, and the people all went home, even the security guards, and she was finally alone. Alone in a museum is right up there with alone in a shopping mall, for things I had to personally realize I was never going to get to do, unless zombies happened. She made her way past all kinds of spooky nighttime things, and to the Pandorica. And when she touched it, it opened wide. The light shone down on her like first contact, and fell upon the stone Daleks, and sitting chained inside was a beautiful girl.
"Okay, kid," Amy said to Amelia. "This is where it gets complicated."
1894 years previous, Rory sat under a black and starless sky, with Amy's body in his lap, telling her the story: "So, the universe ended. You missed that. In 102 AD. I suppose this means you and I never get born at all. Twice, in my case." He asked her to laugh, it's the kind of joke she would like, and when that didn't work he quoted at her: "The Doctor said the universe was huge and ridiculous, and sometimes there were miracles. I could do with a ridiculous miracle about now..."