Sherlock Holmes has a weakness for dangerous, brilliant, enigmatic women. River Song has a weakness for dangerous, brilliant, enigmatic men. When she employs him to track down a mysterious couple and their blue box he's swept up into a world he wasn't even aware existed.

Features: Eleven/Rose, Rory/Amy, River/Sherlock, John, Lestrade, Moriarty
Takes place after "The Hounds of Baskerville" and before "Reichenback Falls" in Sherlock.
Takes place post season 5 Christmas special and pre "The Impossible Astronaut" for Doctor Who.

Sherlock leaned back in his chair. "Rose Tyler is dead. She was born in 1987 and died in 2006 at the Battle of Canary Wharf, as the tabloids called it." He laid three pictures on the table. One was the image that River had originally given him. The second was a grainy picture taken from security footage of One Canada Square. It showed a young, pretty girl—Rose—and an older man-the Doctor-in a pinstriped suit. They were holding hands. The third was of a list of names carved into a slab of granite. 'Rose Tyler' was halfway down the image, circled in black marker.

River raised an eyebrow. "Have you visited her grave? Have you dug up her coffin and seen her bones?" A knowing smile curved her lips. "Don't assume anything, Mr. Holmes, especially when you're dealing with the Doctor."

John thought they were both mad.