Herry's dog goes missing. At the same time Cronus unleashes the three headed beast, Cerberus, on the city. The only thing that can calm the beast is Orpheus's lyre but the heroes must travel to the Underworld to get.
Archie gets jealous when Atlanta starts hanging out with a new guy in school, DJ Panic. What the heroes don't know is that he's under Cronus' control.
Odie is given the caduceus staff by Hermes but lets it fall into the hands of Cronus but breaks it during the process. Odie believes he isn't good enough for the team, so Odie quits the Titans and joins forces with Cronus.
Jay tries to capture Cronus but fails. Now Cronus has the key to a powerful device and he's on his way to Atlantis. Now the heroes must find Cronus does or Cronus will drown the world in water.
Neil can't stop bragging when he captures the gorgon, Medusa. But with all of his gloating, Medusa's sisters seek revenge for their sister, so they kidnap Neil in exchange for Medusa.
Cronus awakens the descendent of Medea, who is the captain of the Woman's field hockey team. Now Jay feels her wrath because Jason scorned Medea. Medea has the rest of the team turned into Amazons now Jay must remember that he has an army of his own, but is it to late?
Jay teams up with Campe, the jailor of Tartarus, to catch Cronus. But when Cronus captures Granny Hercules, Herry takes off to rescue her, playing right into Cronus' hands. Now Campe and Jay have to choose between Herry's life and Cronus' defeat.
Archie opens Pandora's Box, unleashing a horrible plague and little Hope. The plague spreads and infects Atlanta, Odie and Herry. The plague threatens the city's water supply, it's Archie's ancestry that provides the only ray of hope.
Arachne was turned into a spider by Athena during a weaving competition and now she wants to be a human again. Arachne hypnotizes Atlanta to luring the heroes into a trap and their only hope of escaping is to snap Atlanta out of her hypnotized state.
Cronus causes Jay, Neil and Odie to crash on a deserted island by stealing control of the wind Aoelus, the Wind God. Odie is rescued by the nymph Calypso and she wants him to stay with her forever. Meanwhile, the rest of the group heads out to find them and run into a seastorm and a monster. It's up to Odie now to convnnce Calypso to help get the wind back from Cronus to save the others.
Cronus offers the Cyclops that was blinded by Odysseus his sight so he can exact his revenge upon the heroes.
Jay is poisoned by a Chimera, now Jay has to fight fate for his life. Meanwhile Cronus make plans on ascending to Earth now that the prophecy is broken, the others race to the Underworld to save Jay.
Cronus turns an entire commando unit into an army of ants. Cronus is calling out Zeus but he's nowhere to be found and he's the only one that can stop the giant ants and New Olympia.
Cronus frees Sybaris, Queen of the Vampires. Cronus suggests to her that she should kill the heroes as revenge for what Hera did to her long ago.
It's New Year's Eve and Crouns' powers are at their peak! He kills Odie and Jay is the last one to find out. Jay must go back in time and save their friend. Cronus goes back to the Titan War to get another shot at Zeus.