AN: This is the first time I've tried writing River Song, so please bear with any mistakes.
Does your Mother know?
One day, on a small nameless planet in the middle of nowhere when she was just a little girl, Melody met a teenager with fire in her eyes and a gun in her hand. They saved the world that day, the teenager said she did that most days, and Melody didn't see her again but she never forgot that teenager. There had been something familiar about those eyes, that sad, knowing smile.
It was only many years later, when Melody Pond became River Song that she realised who that teenager had been, and it was not what she'd expected. She'd met her again, in a bar somewhere, and River frowned at the girl. She couldn't have been more than sixteen.
"Does your mother know you're out this late?" she asked. The girl smirked.
"She does now. I'm Sky, by the way. Sky Song." And then the girl was gone.
At first, River tried to convince herself that it had been a coincidence that the girl's last name was Song. After all, there must have been thousands of people in the universe with the name Song, right? She hoped so, but every time she remembered that girl, she saw the frizzy hair that was so like hers, those ancient eyes that belonged to the Doctor and she remembered what the girl had said to her. "She does now." She remembered how the blaster she carried looked so like the one the girl had, she remembered the vortex manipulator that had been round the girl's wrist and she remembered the girl's erratic dress sense.
But she was just drawing conclusions, right? It didn't mean anything, right? Wrong. Three months after the Doctor had taken her to see the singing towers of Darillium, River could no longer ignore the fact that she was pregnant. She didn't dare call the Doctor, who knew which version of him would turn up? So she did the only thing she could. She went to New York.
Amy and Rory were so happy to see her, and although they begged her to tell the Doctor, River refused. She knew what happened next, the Doctor had let something slip and she knew that she wouldn't be around for very long. When the babe was born, she shocked Amy and Rory by saying she was going to leave. "River, you can't, she needs you!" Amy said.
"I'm sorry Mum, Dad, but I can't stay. I have to go to the library." She tried to smile through the tears. "You've always wanted a baby Mum, now you can have one." She took her favourite blaster and placed it in the basket that Amy held and turned to leave.
"At least tell us her name," Rory said.
"Sky," River replied. "Sky Song."
They thought that was then end of it, but a year later a confused young man by the name of Jack Harkness ended up on their doorstep. He had River's vortex manipulator and the screwdriver the doctor had made her in his hands and a note from River herself. He said he was to give it to Sky Song. Years later, Sky read the note, the last words she would ever hear from her mother.
Sweetheart,
If you're reading this then Jack has done what I asked for once and delivered my vortex manipulator and screwdriver to you. You should already have my blaster, unless Amy has confiscated it. I'm so sorry I had to leave, but I didn't have any choice in the matter. That's the curse of a time traveller, some points are fixed in time and as much as we might like to, we can't change them. I would say that I want you to follow in my footsteps, to live your life amongst the stars, but it is a dangerous life and really I would like you to quietly live it out in New York with my parents, but I know that won't happen. You may have wondered why you have two hearts, you're part Time Lord sweetheart and I could no more ask you to not travel amongst the stars than I could give it up myself. The vortex manipulator will take you anywhere in time and space, just put in the coordinates and off you go. If you've inherited my hair, the manipulator will undoubtedly make a mess of it, but that's life for you. The screwdriver has many settings, but you're part Time Lord, so you'll probably figure it out. There is one other thing you must know, Sky. Your father is a hero. His name is the Doctor. I hope you find him one day, but you don't have to live your life waiting for that man, god knows I did. Goodbye, sweetheart, and remember that I love you,
River Song.
Many many years after that, when her grandparents had peacefully passed away, Sky strapped the blaster to her hip, the vortex manipulator to her wrist and set off amongst the stars. She ended up in an alien bar, somewhere across the cosmos and nearly walked into a man holding a drink. "Whoa, easy there kid," he said in an American accent, then he frowned. "You're a bit young aren't you, does your mother know you're out this late?" Sky grinned.
"You know," she said. "I rather think she does."