Ex-football star and adventure Harry Johns has become stranded on Dr. Graves' island with his girlfriend Conny. Graves is a psychotic surgeon who has found an obsession with monsters. He has turned the island's inhabitants into ghosts, mummies, werewolves, and witches. Furthermore, in the buildings which they roam are six sleeping monsters including a witch, a mummy, a werewolf, Frankenstein, Dracula, and a hunchback.

These monsters need to be destroyed, and in order to accomplish the task, Harry must find the correct weapon stored in one of the six buildings and use it to destroy said monster, but these weapons are not usually found in the same building as the monster it is designed to kill.

The monsters usually hide at the right end of the building, but in order to reach it, Harry must deal with the inhabitants by shooting at them or using his limited number of Peek-a-Boos to wipe them out of sight. When certain inhabitants are destroyed, they leave behind severed hands which must be jumped over. Among the status bar are six pictures of the monsters, and a picture of a gravestone replaces one of them if the monster is destroyed.