Hercules' good name is sullied when his mortal half-brother, Iphicles, steals his identity. As Iphicles joins forces with the evil warlord Gorgus and prepares to marry Rena, Gorgus' stepdaughter, Hercules sets out to defend his name. But Gorgus and the warrior Pallaeus capture Iolaus and throw him into the perilous catacombs. Hercules then has to descend into the labyrinth to save his friend. Fending off booby traps, flying blades and the Mandrake monster, Hercules frees Iolaus. Iphicles' ruse is then discovered by Rena and which prompts him to fight side-by-side with Hercules to regain her love. Finally Gorgus and Pallaeus are defeated.