Cat Burglar is an unofficial reworking of 1953's Pickup on South Street. Burglar Jack Hogan steals a briefcase which, unbeknownst to him, contains a valuable secret scientific formula. The owner of the briefcase was on the verge of selling the formula to an unnamed (but somewhat slavic-sounding) foreign power. Thus it is that the burglar has the owner, the spies, and the police on his tail. Directed by former Republic western specialist William Witney, Cat Burglar was independently produced by Roger Corman's brother Gene.