Two young men are training for a rowing race on the Tiber. One of them, "Marco" is distracted by a new found love.

Gordon Scott plays Glaucus, the prince of Tiryns, a powerful warrior who goes undercover in Mycenae to infiltrate the evil cult of Moloch, which is exacting tribute from neighboring kingdoms in the form of attractive young hostages, both male and female. Calling himself "Hercules," Glaucus defeats Mycenae's champions and gains the favor of the voluptuous Queen Demetra (Rosalba Neri) whose son, covered in a dog's head mask, has been raised as the living embodiment of the dark god Moloch and receives sacrifices in his sprawling underground grotto.