The warrior Maceus is celebrating with his warriors after a recent victory in Thrace. Looking for his brother Demetrius, Maceus discovers he is dead, killed by Hercules. Demetrius had pretended to want to marry Hercules' mother Alcmene to lead him to his death at the hands of Echidna, the Mother of all Monsters, but was foiled and killed. Maceus vows revenge on Hercules.
On his way to meet a friend in the village of Plinth, Hercules encounters a giant calling for help. His name is Typhon, and he is caught in a boulder, having run afoul of Hera. The goddess wanted Typhon's wife to do evil things, but she wouldn't as long as Tyhpon was around, so she trapped him in a rock for 101 years. Freeing the kind but clumsy giant, the two travel to Plinth together.
Meanwhile, Maceus has found Iolaus, and tortures him to discover Hercules whereabouts. Iolaus refuses, but after he has his wrist broken, he lies and points them in the wrong direction. Along the way, he escapes from the warriors and goes to warn Hercules.
Back in Plinth, initially the villagers are afraid of the giant, but soon discover he is gentle and kind, playing with children and trying to help out, though his clumsiness gets in the way. Encountering Septus and his daughter Breanna, Hercules agrees to help fix up the village after being raided by Maceus and his men. During a conversation with Typhon, it is learned that Echidna is his wife, and his children - the Hydra, the Stymphalian bird, and the She-demon - were misunderstood and have good qualities about them. Having killed those monsters, Hercules does not want to anger Typhon, so he does not mention in detail his fight with Echidna.
Eventually, Iolaus reaches Plinth just ahead of the warriors. Hercules, with some "help" from Typhon, defeats them and sends them running. Witnessing a few signs from Hera, Maceus and his band go to the freed Echidna and vow to bring Hercules to her.
Breanna and Iolaus show signs of mutual attraction at a village dance, but Typhon interrupts. Eventually he learns the evil things Echidna did to Hercules', but refuses to believe and goes to find her. Finding Maceus first, he is told that Hercules killed his children, but Typhon is too kind to vow revenge. Hercules and Iolaus go to find Typhon and Echidna. Encountering Maceus' warriors, Hercules leaves it to Iolaus and goes to the cave where fights Echidna and Maceus, who is accidentally killed. Iolaus soon arrives with Typhon. Seeing her lost husband, and finding out it was all Hera's doing, Echidna relents. She and Typhon happily reunite in embrace, and Hercules and Iolaus slip out unnoticed by the happy couple.