The beautiful warrior woman Xena was intent on securing complete control of the region of Arcadia. To accomplish her goal, Xena decided that Hercules must die. She posed as a maiden in distress and effectively lured Iolaus away from his best friend. Xena then used all her beauty and charm on Iolaus, even preying on his loneliness. Hercules discovered Xena's true identity and went to rescue Iolaus. At first, Iolaus turned on Hercules rather than join him. But eventually Iolaus realized the truth. He and hercules fought Xena and her army until Iolaus was injured. Xena departed, vowing a vengeful return.

Hercules was angry to learn that the warrior princess Xena was raiding villages to increase her power and territory. What Hercules didn't know until later was that Xena's lieutenant, Darphus, was the cruel and heartless one. When Xena spared the life of an infant, Darphus forced her to endure the Gauntlet, a series of trials in which she was punished by her own soldiers. Fleeing on her own, Xena challenged Hercules to a duel - and lost. But he spared her life, so she joined him in defending the village of Parthis from her former lieutenant.

"Unchained Heart" is the 13th episode and season finale of the first season of the television series Hercules: The Legendary Journeys. Written by John Schulian and directed by Bruce Seth Green, it first aired in the United States on May 8, 1995.

Hercules found it increasingly difficult to adjust to life without his superhuman strength. Meanwhile Ares and his nephew, Strife, plotted Hercules demise which didn't help matters. Then Hercules awoke one morning to find his wife lying dead beside him, murdered. He appeared to be the murderer, but in his darkest hour, his friends Iolaus, Xena and Gabrielle came to his aid, defending him against a lynch mob and exposing Strife as Serena's killer. Zeus gave back to his son the gift of incredible strength, and Hercules defeated Strife before the evil young god escaped with Ares.

A lightning bolt from the dying Zeus opened a vortex to a parallel universe, where Iolaus was a jester and Hercules was the malevolent Sovereign. This alternate Hercules and the alternate Xena were lovers, and they were attempting to kill Zeus with Hind blood. Ares, meanwhile, was the god of love, not war, and Aphrodite was a modest, sensitive goddess. When the vortex reappeared, Hercules, Iolaus, the Sovereign and the alternate Iolaus all wound up inside and fought a furious battle. Each managed to return to his proper universe except the Sovereign, who was trapped inside the vortex.

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.