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.

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.