The singing brought tears to her eyes when she first heard it. Standing on a balcony of air, hardened and shaped by the countless songs sung every second of every day for all eternity, River Song looked out over the city of song that the Doctor had promised her, all those years ago.
She looked out, and it was beautiful.
"I promised you," he told her, and he looked so old. "Didn't I promise you? A city of song."
"You did," she breathed, and her chest hurt.
"And you were afraid you'd fall," he said, indicating their balcony. It was just one of thousands, and she could see dozens of people crowded on each of the others. She had been afraid, when she'd first stepped out onto the invisible platform.
She laughed. "I was."
"You didn't," he reminded her. "I'd never let you fall."
Not the planet, the city. No dogs with no noses, just tapas and orange groves. Old Earth. River Song had never smelt anything like it; citrus and sweat. This was disgusting. It was beautiful.
This was when he told her about Rose.
She always loved to hear about his old companions, about those that had taken her position before she had. Susan and Rose, Romana and Donna, K9, Captain Jack and Adric. Those he'd lost, and those he'd had to leave behind. And whenever he told those stories, he'd look at her with such longing, it would break her heart.
And whenever he did, she kissed him.
When he told her about Rose, though, he always cried. And she always kissed away the tears.
He told her the stories, time and time again. And every time he got to Canary Wharf, every time he finished his story, River always asked him the same question.
"And where's Rose now?"
"Oh," he'd say, and look off wistfully, "she's at home."
Whenever she heard him say that, so was she.
There was a man on Ithaca XIX that made books. He was quite the man. Local rumour held that he was over a thousand years old, and there was no one in the universe quite like him. He'd make anyone a book, but he only made special ones for special people.
Or, indeed, special Time Lords.
River had been telling the Doctor all about the difficulties of archaeology, and even though he gently ribbed her for her profession, he always paid attention. She said that it was impossible to remember everything she needed to, and any database would get too crowded with information so as to become virtually unusable.
The Doctor had smiled, and said that he'd find a way to make it easier for her. That was unlike him, River had noted; he wasn't the kind of man to make things easy.
So long before this visit, before he was who he was then, he'd done a favour for the bookmaker of Ithaca XIX. For River Song, the Doctor called in that favour.
He presented her with a special book.
It was blue, and bound so as to look like the TARDIS. And, just like the TARDIS, it was never ending. She could flip through it and always find a blank page. And, again, just like the TARDIS it would take one to anywhere one wanted to go. All she'd have to do was flick from page to page, and she'd find what she was looking for.
She asked him if she'd be able to find him in there.
The Doctor simply smiled, and patted his psychic paper.
Time and time again, River Song had difficulty getting to sleep. She'd lay awake, after writing in her diary, and wait for sleep to claim her. But it didn't, and when it did, her rest was fitful. Unfulfilling.
Only one thing could get her to sleep properly.
He was skinny, and pretty, and his arms were preternaturally strong. He rested his chin on top of her head after making love to her, and he'd tell her everything.
Then she'd fall asleep in his arms.
He never slept. After more than a millenia of life, he didn't need to. No rest for the wicked, and after so long, he was nothing if not wicked.
River Song would always remember falling asleep with him.
And she would always remember waking up alone. Every time.
It was a beautiful sight, the singing towers of Darillium. Made of crystal polished to a high sheen, the towers never stopped keening; it was an orchestra of nature, creating music that would last a century, creating beauty that would last far longer.
"Do you remember the city of song?" the Doctor asked her.
"Of course," River answered, patting her diary. She heard his voice as she said; "You'd never let me fall."
He looked at her then, and he'd never looked older, new suit and new haircut notwithstanding. "No. I'd never let you fall."
They'd started in the city of song, and he knew, though he'd never have told her, that they'd end here, in a city that sang.
"I have something for you," the Doctor said.
He reached into his pockets, bigger on the inside, and he handed her something.
She looked down at the object in her palm. "Your screwdriver?"
He nodded. "My screwdriver."
He'd never give anyone his screwdriver. It was a part of him. It was him. "It was the least I could do, River. You've given so much of yourself to me… it was time for me to give you something."
"Because, River Song, this is the end of our story. Time to stop running."
Tears sprang to her eyes. "I don't understand."
"Time for our story to end. Or start. Depending on how you look at it. Both, kind of." He extended his hand. "Come on. One more trip through the TARDIS. Next stop, anywhere. Everywhere."
She took his hand, and as she did, he leant forward. He whispered something in her ear.
He gave her everything.
He gave her his name.
And as they walked away together, tears were streaming silently down his cheeks.
River Song died that day in the Library.
Her story came to its end.
The Doctor met her for the first time that day.
Their story was only just beginning.