 At the Bainbridge Research Foundation, Professor Franklin Arnold (Ralph Morgan), displays his creation, the Metalogen Man, a robot, to Professor Ernst (George Macready) and three other colleagues. Shortly afterwards, the three associates are killed by Thor (Ray Corrigan, in his for-rent ape suit), a huge ape trained by Ernst, and Arnold, his daughter Babs (Carole Mathews) and Ken Morgan (Robert Lowery), a representative of the company for whom the robot was made, find it has been stolen. Their 15-chapter search for Thor, the robot and Ernst leads to a series of cliff-hanging adventures as Ernst strives to gain control of the robot and the supply of metalogen needed for its production.