Hercules and Iolaus go back to their old home town, Thebes. As they admire the town from afar, Hera's eyes appear in the sky and lightning strikes a building, causing it to become alight. Hercules and Iolaus run to help put out the fire. Hercules uses the water tower to dampen the flames.
Later, the villagers refuse to worship Hera, and tell Hera's men if they do not like it they can speak to Hercules. A female figure with fiery red hair forms from the flames at the temple's altar. She says they will worship Hera "or die." The villager strikes at her with his sword cutting her in two. Flames emit from inside and her body reforms and she kills the villager by breathing fire. She tells the other villagers to "prepare for a world in which Hercules lies rotting in his grave."
Back in Thebes, one villager asks Hercules to stay a while. Hercules watches the villagers sifting through the damage caused by Hera, telling Iolaus that they stand for everything that is right and Hera can just take it all away in vengeance. Iolaus asks how long it has been since his family was killed, Hercules says in the two years they have been dead he has only visited their graves once. Iolaus suggests Hercules takes some time alone, and Hercules takes the opportunity to visit his family's graves.
Hercules has an emotional conversation with Deianeira. At the graves, Alcmene and Jason meet him and take him home. Meanwhile, one of the villagers tells Iolaus about woman made of fire at Hera's temple. Iolaus runs off to tell Hercules. In the woods, he meets the new Enforcer. After a brief battle, she beats Iolaus, leaving him for dead.
Iolaus, using all his will, struggles back to tell Hercules about the new Enforcer, before dying in Hercules' arms. Alcmene and Jason give their sympathy to Hercules, but he tells them he will not let Iolaus die and begins calling for Hades. While screaming for the god, Hercules and Iolaus are transported to the other side. Once there, Iolaus is revived and Hercules tells him that he is dead. When Hades arrives, Hercules tells him that Iolaus is not staying in the Underworld. Hades says he has no choice, but will be going to the Elysian Fields.
Persephone persuades Hades to allow Hercules to get Iolaus back. Hades agrees but tells Hercules he must fight Hera's new Enforcer and it must be done by sunset and Hercules must work alongside Hera's old Enforcer. It is revealed that the old Enforcer ended up in the Underworld. Hercules argues that she was put on Earth with the sole reason to destroy him. Hades says she never had a soul then and if she does a good deed he will know where to send her in the Underworld.
Hercules arrives back on the surface and the Enforcer emerges from the river. Alcmene is frightened by her but Hercules says she is with him. Meanwhile, Iolaus and Persephone talk in the Underworld. While walking, Iolaus points out a group of people who do not appear to be happy in the afterlife. Persephone says they are fallen generals, doomed to remain in the Asphodel Caverns for all eternity, talking about battles and weapons.
Iolaus walks over to one of the men and it is revealed that he is Iolaus' father, Skouros. On the surface, Hercules takes Alcmene and Jason to the Sofia caves, where they will be safe from the new Enforcer. Hercules tells then that the woman from the river is also one of Hera's Enforcers. When the red haired Enforcer enters the cave, she fires a ring of flames around the group. She then places a large rock blocking the entrance to the cave and vanishes.
She reappears outside the cave, using her fiery breath she melts the rock in place. Hercules remembers that the Enforcer is made of water and calls for Jason's knife. Cutting her open she sprays water and douses the flames. In Thebes, the Red Enforcer, leading an army of Hera's men, rampages through the village destroying things and beating people up.
In Hades, Iolaus and his father argue about the past, Skouros argues that there were wars to be fought and Iolaus calls him a coward for deserting his wife and family. Hercules and the others arrive back in Thebes and are attacked by Hera's men. The Red Enforcer seizes Alcmene and pulls her into a building. The Enforcer sees them and quickly follows. She sets about fighting the other Enforcer. Impaling her on a metal spike, she tells Alcmene to run.
The Red Enforcer frees itself from the spike and resumes the fight, while Hercules and Jason continue fighting Hera's men. During the fight the Enforcer cuts off the Red Enforcer's hand, which becomes flame, she points it at the other and she begins boiling. As Hercules enters he finds her dying on the ground with the Red Enforcer no where to be seen.
Hercules thanks her for saving his mother's life and for that he will always be her friend. She tells him she is happy and disappears in a cloud of vapor. Later, Alcmene asks Hercules what will happen to the Enforcer now she is dead. Hercules says Hades has to decide. Alcmene tells Hercules not to go after the Red Enforcer alone, but he says he has to save Iolaus.
When Hades sees a miserable Iolaus, Persephone explains that he is thinking about his father. Iolaus starts thinking that he and his father are not so different. Skouros approaches Iolaus and tells him that he lied earlier; he thought about him and his mother everyday after he left them. Iolaus apologizes for the way he treated his father earlier. After their conversation Hades promotes Skouros to the Elysian Fields.
Meanwhile, Hercules goes to Hera's temple and begins a vicious fight with the Red Enforcer. He finally defeats her, when he uses a shield to block the flames, which begins spewing from her stomach. With Iolaus safe, Hades shows him and Hercules a window into the Elysian Fields, where they see Skouros and the Enforcer walking together. Iolaus suggests Hercules should go and see his family while he is in Hades. Hercules says he can go to a place where he can do more than look. Back at their graveside, Hercules talks to his family again telling Deiraneira that their love will last forever.