Veteran Honor Guard Tomar-Re calls in Hal to help him investigate a Manhunter temple that he has discovered in a distant sector. Hal insists on going in rather than contacting the Guardians and waiting for backup, and Tomar-Re reluctantly follows him. Inside the Green Lanterns find three Manhunters, just like the ones that Hal discovered on Earth. Hal wonders if there is some controlling force but Tomar-Re has confirmed that there is no master communication signal.
The Manhunters activate and attack the Lanterns, forcing them to split their fire and try to contain them. Tomar-Re trips once while Hal topples a pillar on it, but the androids are undamaged and fight their way clear. Hal and Tomar-Re retreat only to discover three more Manhunters guarding the exit. The Green Lanterns blast past them and head to Oa.
The Guardian Council assembles and the two Honor Guards inform them what happened. The immortals insist that they destroyed all of the Manhunters and that the few androids that Hal has seen are just isolated leftovers. Hal doesn't believe it and insists that someone is reactivating them, even though Tomar-Re disagrees with him. However, the Veteran Lantern says that further investigation is warranted. The Guardians agree and order Hal to put together a small team to investigate. Before he goes, Hal asks them to give him the use of the Interceptor and they reluctantly agree.
Hal goes to the training center to recruit Kilowog, who is busy training new recruits. Kilowog says that he's happy where he is so Hal offers to fight the most promising recruit. If he wins, Kilowog goes with him. Kilowog agrees and calls over Ch'p, a small squirrel-like Green Lantern. The recruit immediately attacks and soon defeats Hal. However, Kilowog agrees to go with Hal anyway, saying he just wanted to see him fight a squirrel.
The two Lanterns board the Interceptor only to discover that Aya has been replaced with an officious navigational program, Lanos. It takes the Interceptor up immediately and refuses to turn control of the ship over to Hal. Hal orders the computer program to find Aya and it reports that she has been taken to the Science Branch and will be dissected in two hours. They fly to the Science Branch and Hal removes Lanos' datacore deactivating it.
While Kilowog distracts Larvox, the recruit on duty, Hal slips past and goes to the observation overlooking the dissection chamber. He has Ch'p with him and the diminutive Lantern enters the chamber via the message tube. The Lantern on duty, Chaselon, comes in and Hal claims that he's there on an inspection. While Chaselon talks about how boring duty, he sends a message tube into the chamber. Ch'p, having replaced Aya's datacore with Lanos', is hit coming back but manages to fight his way through and leaves with Hal. The Guardian Science Director arrives and begins the dissection. When Lanos protests, she assumes that he's Aya trying to deceive her and continues the operation.
Outside, Hal joins Kilowog and Ch'p gives them Aya's datacore before returning to duty. When Hal and Kilowog return to the Interceptor, they find Tomar-Re waiting for them. Hal assumes that he's there to take them into custody for stealing Aya. However, Tomar-Re apologizes and says that Hal was right: he has discovered that someone sent an activation signal to the Manhunters at the temples.
As they fly away from Oa, Hal activates Aya and she asks where Razer is. He admits that Razer is on sabbatical, and Tomar-Re informs them that he discovered that someone used a low-level antimatter pulse to activate the Manhunters. The veteran Green Lantern agrees that they should investigate and traces the signal to the planet Biot. As they fly down using their rings, the three Lanterns realize that the planet is where the dismantled Manhunters were dumped by the Guardians. Tomar-Re detects another antimatter pulse, which activates the Manhunters below. The androids attack the three Lanterns and Hal has them retreat to a nearby temple structure and seal the doors.
Tomar-Re confirms that the pulse signal came from that building, which is similar to the other temples they've found. Exploring, they discover an automated assembly plant manufacturing new Manhunter androids and realize that each temple across the universe is just such a plant. One of the new Manhunters spots the intruders and the androids attack, while the androids outside break in. Hal orders Aya to open on the building and she brings it down. The Green Lanterns shield themselves with their rings and fly up, but Tomar-Re warns that he's still detecting the antimatter pulse.
A giant figure clad in blue-and-gold armor emerges from the ruins of the temple. The entity, the Anti-Monitor tells his enemies that he has conquered an entire universe and fed on all the planets there, converting them to antimatter. With his Manhunter servants he plans to conquer the new universe and consume it as well. The Lanterns are forced to retreat as the Anti-Matter unleashes a burst of pure anti-energy at them. Aya opens fire, knocking the Anti-Monitor back momentarily, but he returns fire. To cover his comrades' escape, Hal stays behind and generates a ring shield to stop the next anti-matter blast. The energy penetrates his shield and Hal vanishes in a burst of light as Kilowog and Tomar-Re look on in horror.