The film begins with Hercules/Goliath/Emilius entering the underworld and defeating several monsters including cerberus to retrieve the blood diamond of the goddess of vengeance. It is later revealed that king Eurystheus has sent Hercules/Goliath on this task to ensure his death to gain allies who after Hercules' death will join the king in an attack on Ancient Thebes (Boeotia). The episode is loosely based on the twelfth of the Labours of Hercules#Twelfth Labour: Cerberus.