Scotland Yard is searching for Mister X. Will his pursuers catch him in the London fog? Will the detectives find him in time? If they work together, they have a chance. Mister X will try to escape by bus, underground and taxi. One player is Mister X, the other are the detectives. Close observation, clever tactics and a bit of luck are required for this exciting chase. Heed the clues and try to catch Mister X before the escapes!