Robert Lowery, George Macready, Ralph Morgan, Carole Mathews, Willie Best, Jack Ingram, Anthony Warde, Ted Mapes, Eddie Parker, Stanley Price, Charles King, Kenneth MacDonald, Bud Osborne, Ray Corrigan, John Elliott
A famous scientist invents a humanoid robot (the titular "monster"), so a greedy rival scientist plans to steal it for use in his criminal plans. His henchmen often kidnap a trained gorilla (the titular "ape") from the zoo, to aid in the schemes.