An ingenious Yankee mechanic, knocked unconscious in a fight, awakens to find himself at Camelot in A.D. 528. Imprisoned by Sir Kay the Seneschal and exhibited before the knights of the Round Table, he is condemned to death but saves himself by posing as a magician like Merlin, correctly predicting an eclipse, and becoming minister to King Arthur. He increases his power by applying nineteenth-century knowledge of gunpowder, electricity, and industrial methods. However, when he attempts to better the condition of the peasantry he meets opposition from the church, the knights, Merlin, and the sorceress Morgan le Fay.