Charles Laughton plays Kidd, a merchant captain who cons the King of England into allowing him to take to the sea to recover a lost treasure and escort a ship back to London. An old fellow conspirator who he thought dead (John Carradine) and a mysterious young man (Randolph Scott) manage to get on board and cause problems for Kidd.

Captain Caveman is the titular hero of the cartoon series of the same name, he is a caveman brought back to life in the modern age who fights crime and injustice with the aid of his band of female friends: he is armed with a large club and is famous for his battle-cry of "CAPTAIN CAVEMAN!".