En route to Thebes for an important diplomatic mission, Hercules drinks from a magic spring and loses his memory. He spends most of the movie in the pleasure gardens of Queen Omphale of Lydia. While young Ulysses tries to help him regain his memory, political tensions escalate in Thebes, and Hercules' new wife Iole finds herself in mortal danger.

Steve Reevesas Ercole (Hercules)
Sylva Koscinaas Iole, bride of Ercole
Sylvia Lopezas Queen Onfale, of Lidia
Gabriele Antoninias Ulisse, son of Laertes
Primo Carneraas Anteo, the giant
Patrizia Della Rovereas Penelope
Sergio Fantonias Eteocle
Fulvia Francoas Anticlea
Mario Bava