Note the "The Name of the Doctor" derivations, inexact quotations utilised, and reversed dialogue.

She was sitting on the bench in the park, something she seemed to be fond of doing, and watching three children busy themselves on the playground. Her children, was the unbidden reminder. His wife's children…

He approached her, as he often did and sat next to her on the bench. She couldn't see him, of course. Or hear him. He was just so temporary, you know. So fleeting a file was he that he could not be recognised by one so permanent as she. He had an expiration date. In about half an hour, actually, he would be zapped back to reality, to the Library's underside. He was a collection of bytes condemned. But that didn't stop him. He used his short amounts of time wisely. His visits to the Library did not an idle man make, and as much as he would like to just sit with her there, hopelessly unseen, unheard, he couldn't resist from the incessant babble he took such delight in. Always, through the rushing of thoughts and the emotional tumult he seemed to be so apt in working himself into, he talked to her endlessly. Sometimes, he even touched her hand or her arm or her knee. More than once, he kissed her on the cheek to say goodbye, touching her neck lightly…

And always, she was unresponsive. Always, she just watched her children, the two that would only ever know the computer and Charlotte Abigail Lux, the child tragedy. Always, he could just feel the cracks inside him widening, large pieces falling away. He was charred and burnt and so brittle inside, and it hurt so much.

And he was angry. At himself, at River, at the Library, at everything. He didn't know why he kept coming here, hadn't yet figured it out; he always just ended up furious…

Because you deserve it, you bastard. Because you let her die. You let her save you and sacrifice herself. This is your punishment. This is what you deserve.

"They're beautiful, River." He spoke over his convicting thoughts, gesturing to the children. "What are their names, again…? Ella, Charlotte (that's CAL, yeah?), and Josh, was it? ... Joshua? Shame you didn't name him Alonso. I knew a man named Alonso once. Good man, Alonso was. Would have been brilliant, you know, because then you could say…" He stopped himself, his throat tightening. He looked at her as she watched the three virtual children on the playground. "I'm sorry," he said quietly. "Seems I tell you that every time I see you, eh? Every visit... I'll bet you get tired of hearing that old story, anyway. I'm something of a broken record, I'm sure. Well, I'll just have to tell you something new, then, I suppose." He paused. "Ah! … Well, Clara and I, we, uh—I've mentioned Clara, yeah? Companion, very smallish, she is, sort of pocket-sized… Anyway, we just saw Jim the Fish the other day. Now, I know what you're going to say," he spoke quickly, "and no! He is indeed not still building his dam. Surprising, yeah? I thought he'd never finish. But there we were, just last week, at the Dam Opening Ceremony. Ha. Ha ha. That's funny; that was a pun. Did you catch that? Thought of it myself. And aren't I clever! Well, no, actually, that was Jim. He gave a speech, you know, dedicating the dam. He started out with, 'And isn't it nice to finally have this dam thing finished!' and I was just howling; I was in fits." He laughed harder and for longer than he'd meant to, trailing off. "It was delightful, really. I wish you could have been there, Riv. You wouldn't have laughed, though. Just given me a good smack for sanity's sake, some necessary chastising, too…" He let his voice fall away while his thoughts ploughed on, riddled with longing and loss.

He looked at her, then, his face hardening, the smile fading. He said quietly and steadily, "Say something, River Song. Tell me I'm an idiot. Tell me how stupid I am, and that I drive the TARDIS wrong. Tell me I make you mad. Tell me that I dress like your hundred-and-twenty-seven-year-old physics professor." His voice was rising, then, and he began to drift from the realm of rationality. He grasped one of her arms, and still, she looked right through him, her eyes unseeing, constantly fixed on the children across the way. "River, tell me that you hate me. Tell me that you'll call your father in here if I keep telling senseless stories. Tell me that he'll bring his sword. Point your blaster at me. Shake your head and tell me what a ridiculous old man I am." Then he whispered, "River, this kills me." He was shaking now, and his jaw was clenched. His words hissed, sharp and angled. "I can't. Do this," he said slowly. "This hurts so much, River, more than anything, more than I can bear. I just want to die, River. I could have saved you; I should have saved you!" Acidic tears began to burn their ways down his cheeks. "River, I should have—"

She slapped him them, good and hard, a scowl on her face concretely. Her eyes were locked with his. "Shut up," she whispered, rage wavering her voice.

"R-River, how—" the Doctor stammered, shocked.

"I said, 'shut up.'" Though her chin trembled, her lips barely moved as she spoke, and her eyes blazed with passion. "I told you, Doctor, I told you, not one single line. You damned fool. Not one line. Don't you dare regret what happened. It was me; I had to do it." She blinked through the tears that were filling her vision. "I had to do it, Doctor, I…"

The Doctor's eyes were wide, and his mouth took that characteristic "O" shape she was so familiar with. "River, how are you even doing that? I'm not really here…"

River breathed deeply, looking away. "You are always here to me, and I always listen, and I can always see you."

"Then… Then why didn't you speak to me?"

"Because I thought it would hurt too much." She looked at him properly, and the aching in her eyes mirrored his own.

The Doctor tilted his head back, looking at her down his nose. "I believe I could have coped."

"No, I thought it would hurt me… And I was right. Look at you, Doctor. Listen to you. You're always here, and I'm always here, too, and I don't even know how to look at you, how to hear you. I've left, and you're here, always, always..."

The Doctor touched her face gently, his thumb catching a tear that had fallen from its perch. "River, my time is running out; I'll be leaving soon, I have to. My file... Never mind that. River, it's hard to leave when you haven't said goodbye," he whispered.

Her voice had lost some of its previous fragility, and was more substantial now. "Then tell me, Doctor, because I don't know. How do I say it?"

He took her hand in his. "There's only one way I'd accept. If you ever loved me, say it like you're going to come back."

She squeezed his hand in response, looking down. Then her eyes met his. "Well, then. See you around, Doctor."

The Doctor nodded. "Till the next time, Professor River Song." He kissed the back of her hand gently.

"Don't wait up," she said. He smiled at her, but he was fighting tooth and nail to keep the tears from his eyes. He stood, turning slightly, but paused when he heard, "Oh, there's one more thing."

"Isn't there always?" He looked at her.

She was no longer trembling, and she took him into her arms for a moment, her head on his shoulder, grounding herself. "Doctor, listen to me. You listen to me, okay?" she whispered into his ear. "You are forgiven. Always and completely forgiven. It was my choice. It was my choice, and you have to forgive yourself like you've forgiven me." She kissed his cheek and looked him in the eye. "It had to be me. Not one line. Remember that, you old fool. Not one. Yeah?"

"Yes, River. Yeah." He nodded through tears. "Not one line." He moved to embrace her again, but at that moment, his temporary existence as a file in the Library's datacore expired, and he once again found himself in the dim underground of the Library itself, alone but for his TARDIS.