A bump on the head sends Hank Martin, 1912 mechanic, to Arthurian Britain, 528 A.D., where he is befriended by Sir Sagramore le Desirous and gains power by judicious use of technology. He and Alisande, the King's niece, fall in love at first sight, which draws unwelcome attention from her fiancée Sir Lancelot; but worse trouble befalls when Hank meddles in the kingdom's politics.

After straight-arrow district attorney Joseph Foster says in frustration that he would sell his soul to bring down a local mob boss, a smooth-talking stranger named Nick Beal shows up with enough evidence to seal a conviction. When that success leads Foster to run for governor, Beal's unearthly hold on him turns the previously honest man corrupt, much to the displeasure of his wife and his steadfast minister.