For years now, Valkyrie Cain has plunged into battle with Skulduggery Pleasant to keep her loved ones safe. This time, though, the battle involves her little sister when a ruthless killer kidnaps her. Skulduggery is racing to catch up with Valkyrie now and the young sorcerer Omen is not far behind, while Valkyrie is given only six hours to find her sister, or else.
