A mystery drew Hercules and Iolaus to the city of Tantalus. There, the bodies of fallen warriors were disappearing from the battlefields. Hercules learned that Ares, the god of war, was to blame. After King Memnos' death, his son Daulin had assumed the throne, Daulin's sister Poena, had taken up arms against him. She believed Daulin had killed their father. Ares had created the entire situation merely to satisfy the appetite of his bloodthirsty hound, Graegus. After leashing the vicious beast, Hercules explained the truth to Daulin and poena, bringing an end to the family war.

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.

Studio head B.S. Hollinsoffer ordered the producers and writers to a retreat at Camp Wannachuck, where he hoped they would come up with some better ideas for Hercules episodes. Kevin Sorbo, who was really Hercules, arrived at the retreat and offered touching stories about Hercules and a noble death for Iolaus. He also saved his co-workers from three attempts on their lives, all perpetrated by Hollisoffer in disguise. The studio head had been working with Ares in exchange for his own network. Realizing the god of war really existed, the writers then wondered whether there might be a real Hercules.

Dahak, chained to the altar in the body of Ioalus, hatched a plan to kill Ares, which would give him the power to break his bonds. Meanwhile, the demon showed Hercules how he had seduced Iolaus at the moment of death. Apppearing as Hercules, Dahak promised Iolaus the power to set everything right in the world. With time running out, Hercules was sucked into the spiritual world, where he found the real Iolaus. The two friends fought side-by-side once more, sending Dahak into a fiery chasm. Then they siad good-bye, and Iolaus disappeared into a shaft of light.

Hercules jumped through a vortex into the Netherworld. There he found his evil double, the Sovereign, as well as the cowardly double of his late sidekick, Iolaus. Disguising himself as the Sovereign, Hercules learned that Nebula, the parallel world's evil ruler, conspired with Ares to imprison the Gods of Olympus in the Labyrinth of Eternal Memory. Hercules and Iolaus battled a giant snake and entered the labyrinth. After defeating Ares and Nebula, Hercules freed the gods. The parallel Iolaus, wishing for a bright future in a new world, jumped through the vortex with Hercules.

The Archangel Michael was the harbinger of the apocalypse. He released the horsemen War, Famine and Pestilence upon the land. Meanwhile, the late Iolaus, who defied The Light on the other side to warn his friend of the approaching Armageddon, joined Hercules. Despite Ares help, Hercules and Iolaus could not stop the release of the final horseman, Death, whose first target was Iolaus. Determined to save his friend this time, Hercules fell with Death into a volcano. Hercules' sacrifice earned the world a reprieve, and Iolaus was sent back to Earth to continue his life at Hercules' side.

Evander, son of Ares, had the power to create anything he could imagine. Zeus, wishing to make amends with Hera, used the boy to free his former love from the Abyss of Tartarus. Unfortunately, the Titans were released, too. Helios and Oceanus tried to destroy Hercules and Iolaus but succeeded only in destroying each other. Meanwhile, the third Titan, Atlas, attacked Olympus. But Hera turned him into stone, condemning Atlas to hold the weight of the world on his shoulders forever. Hercules and Iolaus took Evander home to Nemesis, while Zeus and Hera began their reconciliation.