A/N: Yes I know the timeline doesn't work, but whatever. This was writing for a request on the BBC Sherlock Fanfiction Challenges at FF (topic/130523/102542326/1/HP-Sherlock-Crossover-Challenge; just add the ff . net part at the beginning). And yes, this is short and yes, this is a total crack!fic... I apologise in advance.

The title comes from the song Running up that Hill, there are a lot of remixes but the original song was by Kate Bush.

Also posted on AO3.

Jim Moriarty, genius and consulting criminal, found himself standing in front of many bowing cloaked forms. Are you confused? So was he.

Tom Marvolo Riddle, AKA the Dark Lord Voldemort, was standing in front of two puny humans, one of which was pointing a metal contraption at him, with red lights dancing all over them beside a swimming pool. As he went to pull out his wand the red lights moved from them to him. Still confused? So was he.

Severus and Lucius both stared in shock as their Lord and Master was replaced with a man their own age with no snake-like features at all who also looked extremely surprised.

Sherlock gaped at the horrific snake-like humanoid standing in front of him. He was almost shocked enough to miss that the sniper dots that had previously been on them suddenly moved targets to the thing that had replaced Moriarty.

While Sherlock was standing there staring like an idiot, John grabbed the gun and fired off a shot directly at the snakeman. He attempted to do something with a long twig of some sort but the bullet hit him straight in the forehead. John then reached out and grabbed Sherlock's arm and tugged him straight through the door and outside the pool.

Lucius pointed his wand at the man at the same time as everyone else in the room. The room flashed bright green with the light if several Killing Curses and the man fell dead. Severus raised an eyebrow at him and he shrugged his shoulders as he took charge.

"D'you reckon it worked then?" Ron asked after a quiet pause. He and Harry were sitting in a Ritual Circle in the Room of Requirement. They had just performed a ritual to swap Voldemort with a person from another time in a place where someone with the ability and means to kill him was located. "I dunno, we'll probably find out tomorrow." Harry replied uncertainly.

"Well, it certainly was very anti-climatic." Hernione murmured. "Let's go to bed, we'll find out in the paper tomorrow whether or not it's worked. Come on, no just leave this stuff here it's fine. We can pick it up over the weekend. Let's go."

And finally, slowly, the Trio headed off to bed.