| With their ship leaking Cesium fuel, four Peacekeeper Commandos board Moya and demand to be taken to the nearest Gammak base. Crichton's plan to avoid detection as escaped prisoners is simple: they lock Zhaan, D'Argo, and Rygel in their cells to play the prisoners, John and Aeryn put on some leftover Peacekeeper uniforms and play the jailers/scientific researchers, and Chiana plays the part of a personal server. It doesn't take too long for the plan to fall apart, though.
The Commandos' mission is to hunt down and capture an intellent virus and return it to the Gammak base. Well, the hunt and capture parts are successful , but Rygel and Chiana frell up the return-it-to-the-Gammak-base part. As soon as Rygel hears that the Commandos have a box with a secret cargo, his acquisitive side takes over and he's compelled to find out what's in it. Chiana has the same idea and the two join forces to investigate and procure.
They manage to get the crate open but when they hear one of the Peacekeepers coming they hide. Thonn, the unsuspecting Commando, gets too near the crate and becomes infected with the virus. He kills one of his comrades but before he can do much more damage, the virus jumps to Chiana. Crichton demands that Larraq, the Peacekeeper Captain, explain what's going on. (The leader of the most-macho contest keeps flipping back and forth between Larraq and Crichton, but right now John has the edge.) Larraq tells them that while the virus is in its single infection stage it has the ability to take over the mind and body of anyone it infests, causing that person to do whatever the virus wants. It's also undetectable while in a person so nobody knows for sure who's "it" at the moment. After it's been in its host for more than an arn, it begins to produce millions of spores, which could spread its infection throughout the universe. The Peacekeepers hope to harness this virus and use it to gain control over their enemies.
Virus/Chiana claims that Rygel killed the Peacekeeper so everyone believes that Rygel has the virus and they all go off on a Rygel hunt. When they catch up with him they shoot him with their "stasis gun", the UT equivalent of the tranquilizer dart. Rygel ends up locked in the crate waiting to be taken to the Gammak base where the virus will be extracted, leaving him dead.
Meanwhile, Chiana passes the virus to Crichton and then she has no clue that it was ever in her. Apart from a little dizziness and a slightly acidic metabolism, there isn't any other way to tell that she had it.
Virus/John kills Hassan, the Peacekeeper scientist who's the one most likely to detect where/who it is at the moment. He also destroys the stasis gun. Zhaan tests Chiana for acidity and, when it comes up positive, they know that she had it and that Crichton is most likely the current host. As soon as they accuse him, he smashes Aeryn in the face and tries to escape but he's overpowered when everyone else piles on top of him. When they all get up again, Crichton's a little disoriented and dizzy so we know that the virus jumped again, but we don't know who has it.
Of course everyone is pointing guns at everyone else while waiting for Zhaan to concoct some glop to test for acidity. Since a person once infested is immune, John and Chiana aren't suspect. Zhaan takes the glop first and is found virus-free, then Aeryn and Thonn who are also free. This leaves D'Argo and Larraq as the remaining possibilities. John injects D'Argo, who's uninfected, so that only Larraq is left. He starts shooting at everyone, they shoot back, and unbelievable as it seems, everyone misses everyone else from a distance of about three feet.
Larraq races off but Aeryn catches up with him. He grabs her, shoots and kills Thonn, then demands that John and D'Argo take him to the Gammak base so he can infect the whole place. They refuse. In retaliation (and to keep them busy while he escapes), Virus/Larraq stabs Aeryn with an enormous knife, drops her to the floor and heads for his ship.
After D'Argo reminds him the he can't be reinfected, John goes after Larraq. Chiana catches up to Larraq first and, trying to stop him, she jumps onto his back. He throws her off, but she manages to steal his ident chip in the process. She tells Pilot to close the doors but John countermands the order. He asks Pilot if the Marauder is still leaking Cesium fuel. It is, so John tells Pilot to let Larraq go. Once Larraq is clear from Moya, John tells Pilot to initiate StarBurst, not the whole process, just the first step. The spark sets the Cesium trail on fire and the Marauder explodes taking Larraq and the virus with it.
Zhaan managed to keep Aeryn from dying but it was a very close call. Crichton is sitting next to her when she wakes up and he's staring at the weapon he used to kill Hassan. He's devastated by his actions while the virus was in him. He tells Aeryn that Larraq barely missed her heart and she replies that it was closer than he thinks.
In this episode it seems to me that John is becoming more of a Peacekeeper and Aeryn less. Crichton committed two deliberate murders in A Bug's Life. Even though Hassan died because of the virus in John, he still held the weapon and took her life. Larraq's death appears to give him a lot of satisfaction. It seems to me that John has more than one motive for blowing him up - kill the virus to save the universe is probably his number one reason. But there is also revenge for stabbing Aeryn and perhaps a bit of jealousy, too. He feels worse about killing Hassan when it wasn't his fault than he does over
Aeryn, on the other hand, is feeling the death of her dream. She watches a Peacekeeper commando team in action and it's almost like a slap in the face for her. She knows that she'll never again fit into the Peacekeeper world, and it's a bit symbolic when Larraq stabs her.