In one of Ares's temples, Ares is swinging around a sword made from the metal of Hephaestus, a metal which he's considering giving to a "chosen few", when a leather-clad goddess named Discord appears. She immediately brings up a monotheistic cult that has her worried, but Ares assures her that a mortal he considers "exceptional" currently controls the cult's temple and that without it, the cult isn't much of a threat. Discord, however, isn't reassured, and wonders why he doesn't just go ahead and destroy the temple himself. Ares counters that Discord doesn't want to go up against the cult's deity anymore than he does, and insists that destroying the temple has to be left up to a mortal. Meanwhile, Xena and Gabrielle are walking along, having a philosophical discussion, when they come across some prisoners being taken back to Brittania to stand trial. Xena and Gabrielle continue on their way, when one of the prisoners, Khrafstar, insists to his captors that he and his people will never submit to Caesar. This gets Xena's attention, and she decides to free the prisoners. Afterwards, she asks what Caesar wants with Khrafster, and he explains that he's been recruiting mercenaries to help Boadicea fight Caesar. Xena then asks about Boadicea's husband Persuticus, and that's when she learns that Persuticus is dead. She agrees to accompany Khrafstar, who's apparently a priest of the "One God," back to Brittania, where she plans to help Boadicea destroy Caesar.
The next day, as they make their way north, Xena tells Gabrielle and their new traveling companions to rest while she goes to check out a nearby harbor. As Gabrielle and Khrafstar have a seat under a tree, Gabrielle and Khrafstar discuss Xena's apparent hatred for Caesar. Khrafstar says he's glad Xena's on their side, adding that Caesar holds 'their' temple and that he hopes Caesar hasn't destroyed it yet. Gabrielle asks if Khrafstar's god has a name, and he replies that he does but that they're not permitted to speak it. Meanwhile, on her way back from the harbor, Xena detects Ares's presence, and demands he show himself. He does, noting that Xena still seems "miffed" about the incident with the Furies. He tells her to get over it, before bringing up Caesar. He tells her that Caesar currently controls a temple, but that he refuses to destroy it just yet, meaning it must be important to him. He adds that it'll humiliate Caesar if she destroys it, but rather than seeing right through Ares's attempt to manipulate her, she walks off, pondering what he's said. Later, Xena and Gabrielle board a ship to Brittania with Khrafstar and the others. As Gabrielle and Khrafstar sit below deck, Khrafstar tells her about the god he worships. He says that, like love and friendship, people can't see his god, but also like love and friendship, they'll soon feel the effect of the one-god when he "brings his kingdom to Earth." Just then, Xena appears, and as she goes to polish her sword in a corner, Gabrielle asks her about Boadicea. Xena explains that she allied herself with Boadicea in Gaul a long time ago, just long enough to take control of Boadicea's army. After taking control, Xena had ordered Boadicea be killed, but she'd escaped and joined forces with Persuticus. Xena defeated them, however, and the two retreated to Brittania. Just as Xena finishes telling her story, she's summoned above deck, where a Roman captain relays an order from Caesar that they're to return to Gaul. Xena seemingly agrees, telling him that they'll set sail soon. However, as soon as the captain's gone, Xena climbs up to the crow's nest, and signals someone on the shore using her sword. A little bit later, the captain is alarmed to learn Xena's ship is heading north, and immediately leads his men to the north part of the beach, only to find Xena has already come ashore. Suddenly, a warrior woman rides up on a chariot, and is identified by the captain as Boadicea. She, Xena, and Boadicea's army get into a skirmish with the Romans, until eventually, the Romans decide they've had enough and call for a retreat. As they're retreating, though, they surprise Gabrielle and Khrafstar in some nearby woods, and capture them, causing Gabrielle to drop her staff. As she and Khrafstar are being hauled back to the Romans' camp, the staff is found by one of Boadicea's men.
That night, in Boadicea's camp, things are tense between Boadicea and the Warrior Princess, as Boadicea apparently still hasn't forgiven Xena. Boadicea then heads to her tent, while Xena asks one of the men about Gabrielle, only to learn she and Khrafstar never made it to camp like Xena was apparently told. So, Xena barges into Boadicea's tent, confronting her over the lie. Boadicea admits she lied but only because she knew Xena wouldn't have left otherwise. She then shows her Gabrielle's staff, informing her that Xena's friends have been taken by Caesar. Boadicea figures Gabrielle and Khrafstar might already be dead, but Xena reasons that Caesar won't kill Gabrielle until he can figure out how to use her against Xena. Meanwhile, in a tent in Caesar's camp, Gabrielle assures Khrafstar that Xena's going to rescue them, just as Caesar makes his presence known, having been sitting in a high-backed chair that was facing away from them. Gabrielle quickly backtracks, insisting that Xena doesn't even know who she is, but Caesar sees right through her lie and orders his captain to take her and Khrafstar to a nearby hill at dawn. In the meantime, Xena and Boadicea prepare to attack Caesar at dawn. Xena says Caesar's weakness is his belief in his destiny, and Boadicea replies that it sounds a lot like the Xena she once knew, with whom she entrusted her life. Xena asks why Boadicea trusts her now, and Boadicea replies that she doesn't but that she doesn't have a choice as Xena knows how to wage war against Caesar. Back in Caesar's camp, meanwhile, Gabrielle asks if Khrafstar has faith in his god, and he answers that he does. He tells her that he used to have a farm in Gaul where he worshipped the Olympians, but then one day, a warlord came and nearly killed him. Some travelers from the East found him as he lay dying, and while they cared for him, they told him about their god. However, he didn't start to believe until he found the warlord again, already wounded from battle, and was filled with a light as he stood over the warlord, holding a sword to the warlord's throat. According to Khrafstar, the one-god made him see that even the warlord had a purpose, and he decided to let the warlord live. As he finishes telling his story, Gabrielle opines that the kind of faith Khrafstar possesses in his god "sounds wonderful." The following morning, Caesar informs his captain that overnight, Boadicea and her army gave up land that they had fought so hard for, confident it's a trap set by Xena. He decides to take the land anyway, hoping to draw Xena into one big battle. Then, Caesar has Gabrielle and Khrafstar hung up on crosses on a nearby hill, and orders Gabrielle's legs be broken, as it would "mean something" to Xena.
Just as Gabrielle's legs are about to be broken, Xena leads an ambush on the Romans, while Caesar watches from a distance. Afterwards, Xena gets Gabrielle and Khrafstar down from the crosses, then tears up Caesar's banner and waves it around in defiance. A little bit later, in a cave that's being used as a hospital, Xena grills Gabrielle about Caesar. Gabrielle mentions an aura Caesar has about him, and Xena warns that it's the same thing that draws a moth to a flame, "with pretty much the same result." Xena then returns to Boadicea's tent, and fills her and her army in on Caesar's strategy of divide-and-conquer. Boadicea brings up the temple of the one-god, pointing out that if they leave it in Caesar's control, they'll have the Romans at their backs, which is why Xena insists they take it. Later, outside said temple, Xena, Boadicea, and their army attack, and quickly manage to wrest control from the Romans. Then, as Xena and Boadicea prepare to face Caesar in battle, Xena notices Ares standing nearby, and goes to talk to him. He demands she destroy the temple, shouting that this world was created by the Olympians and that there's no room in it for a monotheistic deity. Xena counters that before the Olympians, it was the world of the Titans, suspecting that what Ares is really afraid of is being overthrown like the Titans were by Zeus. He warns that whatever she thinks of him and the other gods, at least she knows them and knows they aren't evil, which, according to Ares, is more than can be said about the one-god. Xena, however, refuses to listen, arguing that Ares has given her no reason whatsoever to trust him. Back at the temple, meanwhile, Gabrielle is there as Khrafstar and the others prepare to celebrate with a ceremony of rejoining. However, changes were apparently made to the ceremony recently, so a priestess named Meridian takes over for Khrafstar instead. The ceremony quickly turns dark as Meridian speechifies that the way must be prepared for their god using innocent blood. As Khrafstar appears stunned at this new development, he and Gabrielle are captured, and he's tied to the altar. Meridian is given a dagger, and as she prepares to sacrifice Khrafstar with it, she declares that the "hand of Dahak" will end the world as we know it. Before Meridian can deliver the fatal blow to Khrafstar, Gabrielle breaks free, and saves him, taking the dagger from Meridian. Gabrielle starts to free him from the altar, when Meridian attacks and Gabrielle's forced to kill her. Then, as Gabrielle stares at the blood on her hands, Khrafstar gleefully informs her that by giving Dahak her "innocence of evil," she's just ensured that the kingdom of Dahak will be brought to Earth. With the realization of what she's done and that it was all a trick, she collapses to the floor, screaming.
Meanwhile, on the battlefield, as Xena and Boadicea prepare to go up against Caesar's army, Boadicea acknowledges that Xena isn't the person she once knew, though she still can't bring herself to forgive her. She does, however, graciously thank Xena for her help, then she and Xena clasp forearms, just as Xena notices a storm brewing over the temple and suddenly worries for Gabrielle. As Xena goes to check on her friend, she finds Meridian's body on the altar, then finds Gabrielle covered in blood. Gabrielle tearfully admits that she killed Meridian, but Xena refuses to believe it was anything but an accident. Just then, Khrafstar appears, and thanks Xena. He explains that his god, Dahak, is a dark force that will bring about "the cleansing fire of war to the world, a war begun of innocence," and that it was Xena who brought Gabrielle to him, all because of her hatred for Caesar. Xena angrily realizes that his god isn't the "one-god of the Israelites" like she and Gabrielle were led to believe, before a fire erupts around the altar and grabs Gabrielle by the ankles, dragging her towards it. Xena tries to save her, but Khrafstar stops Xena and they fight. Suddenly, the altar explodes in a burst of fire, forcing Xena and Gabrielle to cover their eyes. When Xena looks again, Gabrielle is suspended over the fire but otherwise fine. Before Xena can attempt to retrieve her, Khrafstar suddenly transforms into a demonic creature known as the Deliverer. As he and Xena fight some more, the flames engulf Gabrielle, wrapping around and around her as she's powerless to do anything. During Xena's fight with the Deliverer, she realizes that he has a temper, so she moves in front of the fire and goads him into attacking her. Thankfully, he falls for it, and she manages to toss him into the flames. As the fire returns from whence it came, Xena catches Gabrielle, just as the temple starts exploding all around them. Afterwards, Xena holds Gabrielle to her, as Gabrielle sadly remarks that everything's changed. They continue to sit among the ruins, which now resemble Stonehenge.