Detective Inspector Eden Brooke searches the body and finds no wallet or papers, save for a cinema ticket dated six months earlier. PC Vanessa Hill - a recruit to The Borough police from Girton College - uses her skills in fine art to sketch the dead man's face for a poster. An autopsy reveals the only clue to his death is the wound left by a hypodermic needle in the back of his neck. Brooke has a very puzzling case on his hands .