The Manhunters arrive at the planet Zamoran and attack the citadel of the Star Sapphires. Their queen, Aga'po, joins in the planet's defense.
Aboard the interceptor, Razer scans for Aya. However, Kilowog points out that it will to be difficult to find her since she was their nav computer. Razer insists that they need to help her because she's confused, but Kilowog warns that she deliberately chose to merge with the Anti-Monitor. Hal agree with Razer and they wonder where Aya is.
ya in the Anti-Monitor's body lands on Zamaron and emerges from the shell. She demands an audience with Aga'po and says that she is there to destroy the destructive emotion of love. Aga'po insists that love is a strength but Aya says that love was withdrawn from her, leaving her in pain. She is there to punish them for promoting love and Aga'po opens fire without effect. Aya blasts the queen back and tells the Star Sapphires to surrender. Gi'ata asks for permission to tend to their injured queen, but Aya tells her that ultimately it means nothing.
Hal suggests that they fly to Oa at ultra-warp and scan for Aya, but Kilowog warns that without an AI navigator, one mistake could kill them. Razer agrees with Hal and they set course.
Gi'ata defends love, saying that it will eventually bring peace and harmony to the galaxy. When she says that she feels love, Aya confirms that it is for Hal and points out that he loves another so that love has brought Gi'ata nothing but pain. Gi'ata is unable to explain how love will save the galaxy but says that they learned of the power of love from their teacher. Aya demands to see the teacher and tells them to teleport her to Zamaron. When Gi'ata says that their teleporter will only reunite beings who share love between them, Aya informs her that she's wrong, touches her head, and then powers up the teleportation device as Gi'ata collapse.
Carol Ferris, in the middle of eating dinner, steps through the portal. Gi'ata apologizes and explains what happened, and Aya tells Carol to convince her that love shouldn't be destroyed and the Zamarons along with it. Carol stammers for an answer, saying love is kind, but Aya tells them that her lover gave her pain by revoking it. Finally Carol says that love is putting someone else's needs before one's own. Aya asks who she loved and Carol admits that she loved Hal and always will, and she doesn't hate him. The AI decides to test the power of love versus hate by staging a trial by combat.
Razer eventually plots a course for Oa and Hal gives the order to proceed, insisting that they can fly on instinct to avoid any obstacles. Kilowog engages the ultra-warp and they depart.
Aya summons hate's champion through the teleport portal: Atrocitus, freed from his cell on Oa. When he tries to attack Aya, the AI freezes him in mid-air and explains that he will fight Carol, love's champion. Gi'ata tries to intervene but Aya points out that the Star Sapphire said Carol was love's greatest champion. When Atrocitus wonders why he should agree, Aya offers him his freedom if he wins along with the death of Hal's love. Gi'ata gives Carol her rejected former ring and Aya gives Atrocitus his ring to make it a fair fight.
The interceptor comes out of ultra-warp and Hal narrowly avoids a star. He manages to pull the ship away but Kilowog says they're not going to risk it again.
Carol and Atrocitus go outside and Carol asks Aya to call it off, but the AI tells Carol to fight or die. Atrocitus opens fire and Carol does what she can to defend herself. The Red Lantern smashes her aside but Carol uses the ring to bring her the one she loves.
On the interceptor, a teleportation portal opens and Hal sees Carol fighting for her life. He flies through the portal before Kilowog can stop him and it closes behind him.
Atrocitus grabs Carol and smashes her to the ground, but Hal emerges and knocks him away. Gi'ata points out that only the strength of love could bring Carol a hero and wishes Hal well.
Kilowog and Razer realize that Hal has been taken to Zamoran, and they can only get there by ultra-warp, and Kilowog agrees to try again.
Hal and Atrocitus continue fighting but Atrocitus has the upper hand because of his long rest and imprisonment. When he prepares to kill Hal, Carol joins the fight and combines powers with Hal. Atrocitus knocks Carol unconscious and subdues Hal when he flies to her aid. As the Red Lantern prepares to kill Hal, Gi'ata flies in front of him and takes the brunt of is fire blast. Hal cradles her in his arms and then turns and beats to the point of unconscious. Carol delivers the final blow and they fly to Gi'ata, who says that there is no greater honor than to die for love.
Aga'po tells Aya that she has her proof that love is the strongest force and goes to her minion. However, Aya says that Atrocitus lost, proving nothing, and sends him back to his cell. Hal tries to get through to his former comrade, offering his help, but she says that love only led Gi'ata to her own destruction. Aya decides to eliminate all life and replace it with emotionless machines. Hal tries to get through to her, saying that she's as alive as anyone, but Aya merges back with the Anti-Monitor. When Hal and Carol attack her, Aya easily immobilizes them and prepares to blast the planet apart. Before she can strike, the interceptor arrives and Razer flies to her and asks what she's doing. She declares that destroying one planet at a time is inefficient and sets out to find a way to set her plan in motion in one effort, remaking the universe in her own image. Aya and the Manhunters depart, leaving Razer to look forlornly after his friend.
Later, Aga'po thanks Hal and Carol for their help and asks if Carol will keep the power ring. Carol agrees to keep it and Aga'po opens the teleport portal to send her back to Earth. Before she goes, Carol gives Hal a kiss on the cheek and thanks him for being there when she needed him.