Donavon is readying her team when a techie bursts in with an urgent summons to the surveillance wing. Turning to Perkins (the poor boy looks terrified at being told the keep everyone here, she'll have to keep him away from Sherlock or he won't last the week), she storms off to see what on earth warrants her attention.

It is a scene of utter pandemonium.

Papers and wheeled chairs fly from wall to wall and mingle with shouts as numerous techies try to figure out what hit them. It takes only a brief observation to determine what has them all so stirred up.

A mass of screens dominates the room, showing footage from the CCTV cameras that cover London. At least, that's what they usually do.

They aren't now.

Donovan curses a certain consulting detective and his shouldn't-be-scary-but-is partner to hell and back as she surveys the damage.

All of the cameras are functioning (she hopes), but that's not what's being reflected here. The screens covering the east end of London are showing…EastEnders. The north end is screening all of the Harry Potter movies at once, the South London cameras are playing host to the entire first season of Being Human.

The West End is showing…actually, she isn't really sure what it's showing. There's too many people crowded around the screens to tell.

But judging by the soundtrack and laser noises…Oh, hell.

It's Doctor Who.