Okay, my first Doctor Who piece. I confess that the chances of my doing the show justice are unlikely, but it's just that this one moment was such a moment of fanfic bait that I couldn't refuse the opportunity. I hope you all enjoy it.

I own nothing.

"You know what they say." The Doctor stands just outside the TARDIS, still reeking of discomfort and confusion. "There's a first time for everything." With a slightly nervous smile he disappears inside. The sound of the door slamming is like River standing in front of Heaven and hearing the gates close shut against her.

River's hand, curled against the bar, tightens almost imperceptibly. "And a last time," she rings out hollowly, and she watches as the TARDIS fades away into nothing. Her face has paled and slackened despite herself, and she doesn't think she's come this close to that thick, cloying, unbearable grief she once had in an eternity.

River Song, notorious inmate of the Storm Cage, wonders how long it will take for the guards to notice she's returned to her cell, all neat and orderly and cooperative. The usual rate is about three hours, but she's gunning for four this time—there's been a bunch of new guys lately, so you never know.

Four hours, or my instincts are slipping.

Lying on her back on her bunk, staring up at the ceiling and listening for the telltale sounds of running footsteps, River can't quite bring herself to sigh.

"There's a worse day coming for me."

It's just starting to really sink in. River Song, you knew this couldn't last. River Song, you know how time works with you and him. You knew the best days were going fast, and now they are gone.

She knew. Oh yes, River knew it was going to end soon. It just snuck up on her so fast.

That day will come, and it's coming fast. River remembers the grief that flashed over the Doctor's face when they first met—

"Think about that. Impressionable young girl, suddenly this man just drops out of the sky. He's clever and mad and wonderful, and knows every last thing about her."

—and she didn't have a clue who he was. River looked at him, frowning and said, "Sorry, but I don't think we've met," and such an echo of grief flickered in the Doctor's eyes that it threatened to drown them both.

"Of course not; innocent little girl like you wouldn't know a man like me."

River had laughed at this—not a harsh laugh, not a mocking one, not even a bitter one, but a genuinely amused laugh. No fifteen-year-old girl could be less innocent than fifteen-year-old River Song. If he knew anything about her, than this madman had to know that.

Years (eternities) later in her little cage, River wonders about that. The Doctor knew everything about her, and it's starting to bother her. He knew things he shouldn't have known and it's starting to seriously bother her.

And eventually, he'll know nothing at all, and when he looks at me he'll ask me "And who are you?"

That's the rub. That's where it all ends for her. River knew this would happen but really, it's just now starting to sink in. She's just now starting to think about it.

He looked at me like I'd gone mad. That's it. River's had her wakeup call. The dream was wonderful and she wishes she could have stayed there, but it was just that, a dream. It had to end eventually. She knew that.

Every time will be worse and worse. The Doctor will be more distant every time she sees him after this, further away. He'll understand less and less and River, River will just watch him float away in that little blue box of his for the last time.

She lives for the days she sees him, but it gets worse every time.

There's always last times. There's a last time for everything.

River hears the clatter of boots against cold ground and the familiar shouts. Word has gotten out: River Song has returned to Storm Cage.

This time, she can't quite bring herself to enjoy the look of shock on the guards' faces.

"The day's coming when I'll look into that man's eyes, my Doctor, and he won't have the faintest idea who I am. And I think it's going to kill me."

It just might.