Hope, the treacherous daughter of Dahak and Gabrielle, went to the Ixion Caverns and freed Callisto. Hope gave the warrior-goddess a mission: rid the world of Hercules. Callisto joined forces with Ares, and the two reopened the vortex to the alternate universe. When the Sovereign appeared, Ares snatched his pendant of Hind's blood -- the only substance that can kill a god. But Callisto ripped the pendant from Ares' neck and used the blood to kill Strife. Hope then sent Callisto back in time to kill Hercules' mother, so Iolaus convinced Ares to send him back as well.

While Hercules and his double, the Sovereign, were stuck in the Netherworld, Iolaus traveled back in time to protect young Alcmene. But he couldn't prevent Callisto from killing Hercules' mother. Callisto then found her own family and, through a series of instinctive actions, she killed her mother and father. As more events began to go wrong, Hercules sent Iolaus a telepathic message: Get the Chronus Stone from Xena's scepter to travel back in time without Ares' help. Using a makeshift lightning rod, Hercules joined Iolaus in the past and sent Callisto back into the vortex, setting the timeline right.

Merlin hurled the vicious warlord Arthur of Camelot and his sorceress advisor Mab a thousand years back in time to Hercules' world. But Mab helped Arthur conquer Britannia. Later she wanted to go back to her own time, and to do that she needed to kill young Merlin with the sword of Excaliber. Hercules and Morrigan captured Arthur and the sword, but mab took Merlin hostage. A fierce battle ensued, during which Hercules dispatched a giant knight and a reformed Arthur displayed newfound heroism. Merlin smote Mab, and Arthur returned to his own time as a proponent of peace.

Sin came looking for Hercules in the guise of Serena. She said she needed Hercules' help to recapture Xerxos, a murderer who had escaped from her world of evil souls. In truth ""Serena"" was in league with Xerxos. She poisoned Hercules in hopes he would take a life in anger, which would condemn his soul to her domain. But Iolaus was able to keep Hercules from killing Xerxos. The murderer found his sister, the criminal Arciana, and encouraged her to reform before it was too late. Then he and ""Serena"" returned to their realm.