Severed (Transworld Publ. Ltd UK)

You wake up in a strange room on a bed covered in blood. You have no idea how you got there. Beside you is a dead girl. Your girlfriend. The phone rings, and a voice tells you to press play on the room's DVD machine. The film shows you killing your girlfriend. Then you're told to go to an address in East London where you're to deliver a briefcase and await further instructions. There's no way out. If you're to survive the next 24 hours, you must find out who killed your girlfriend, and why. Before they come for you too...