"I think not," is his reply, and the DRDs in the bay cut loose with their welding lasers. The gun flies from Larraq's hands, and the Peacekeepers dive for cover. When the shooting dies down, Crichton tells them he'll be happy to help the squad accomplish their mission, but only as an equal. Surprised, Larraq agrees.

Larraq's not nearly as forthcoming about his mission -- he's got a box to deliver to a secret base, and he's not about to tell them what's in it. That's not much of an explanation, but it's enough to get Rygel's attention.

Meanwhile, the other three Peacekeepers have brought the box to a cargo bay. The big bald sergeant is named Thonn, the quiet female lieutenant is the science officer, named Hassan. The last Peacekeeper is named Rhed, and given that he dies before the act is out, his last name had might as well be "Shirt."

In the cells, D'Argo is ready to ambush the Peacekeepers, but Crichton is elated by the success of his impersonation and so wants to keep it up to learn what's happening. Unfortunately, Rygel's vanished down the hidden escape route in his cell, and they have to find him before he blows their cover.

As they start the search, they're nearly walked in on by Thonn, who's patrolling the ship. Crichton hesitates convincing D'Argo to get back in the chains, forcing D'Argo to fake an escape attempt so that Thonn can "rescue" Crichton.

Meanwhile, a rapport between Aeryn and Larraq blossoms as the Peacekeepers trade service records, even though he won't tell her anything about the box.

Chiana makes a duplicate key for the box and returns to the cargo bay, where she finds Rygel. Together they open it, exposing a bizarre alien. Before they can figure out much more, Thonn walks in.

Chiana and Rygel hide, but Thonn spots the open box, then goes to takes a close look at the alien. Thonn starts twitching, and Rhed picks that moment to walk in the cargo bay and live up to his name of doom. He has just enough time to warn Larraq before Thonn blows him away.

The alarm goes out. Pilot reports the shot to the rest of Moya's crew and D'Argo grabs his sword and heads for the door, happy to end the charade.

In the cargo bay, Thonn kills the alien in the box, then spots Chiana. He nearly kills her, then changes his mind, grabs her and kisses her. As Thonn suddenly looks confused, Chiana clobbers him. She's just about to kill him when Aeryn and Larraq arrive.

After looking around, Larraq announces, "It's escaped." Crichton arrives just in time to hear this -- and as he asks what "it" is, we see Chiana hiding in the shadows. Her eyes have an eerie blue glow.

Larraq now explains what's going on. Their mission was a fugitive retrieval, but the fugitive is unusual for being an intelligent virus capable of transferring itself to any host. It can currently infect only one person at a time, but given an hour in that person's body, it can create millions of spores to infect others.

Chiana comes out of the shadows just as Larraq starts to interrogate Thonn, who has regained consciousness and can't remember the last few minutes. She tells everyone she saw Rygel open the case, then knock out Thonn, take his weapon, and shoot Rhed. Larraq immediately leads Thonn and Hassan out to search for Rygel.

Crichton draws Aeryn aside to tell her he's ready to drop the masquerade now. She agrees with him that this is a disaster, but notes that they have nervous, trigger-happy Peacekeepers on their hands and they'll have to play out the deception as best they can.

To make things worse, D'Argo is out hunting Peacekeepers, and there's a tense standoff in the corridors before Crichton manages to persuade him and Zhaan to stop fighting and help find Rygel.

After splitting into pairs to search the ship, Aeryn and Larraq find Rygel hiding in a small shaft off the central chamber and call the others. Rygel desperately tries to tell the rest of everyone what really happened in the cargo bay, but nobody's listening. As Larraq hits Rygel with a blast from a stasis gun, Chiana turns to Crichton, and the virus moves to him.

With Rygel captured, Crichton, now possessed, takes Zhaan and D'Argo back to their cells. Zhaan protests -- she wants to try to work on a cure for the virus. Crichton promises to talk to Hassan about it. In the meantime, they're to stay in the cells and stay quiet. He locks them in, slapping Zhaan to impress the patrolling Thonn.

In the cargo bay, Aeryn asks Larraq what will become of Rygel, and learns that the process of leaching the virus from him will be fatal. Larraq also tells Aeryn he's impressed with her, and suggests she might want to join the Peacekeepers' special operations division.

Crichton finds Hassan in the transport hangar. As she asks him about Zhaan's herbs, he beats her head in with a metal bar and smashes the stasis gun, which she had brought with her to the hangar.

In the cells, Zhaan has asked Pilot to call Chiana. When she arrives, Zhaan quickly verifies than she's been a bit dizzy, then asks her to lick Zhaan's bedcover. Chiana's saliva has an acid reaction to the fibers, confirming that she was possessed by the alien, and Zhaan and D'Argo start to figure out where it is now.

On the bridge, Crichton orders Moya to accelerate towards the Peacekeeper base and needles Larraq about his capture of the virus. He's interrupted by the arrival of D'Argo, Zhaan and Chiana, as well as Thonn, who has found Hassan's body.

A firefight is averted when Aeryn kicks aside Larraq and Thonn's weapons. Zhaan quickly explains her belief that the virus isn't in Rygel but is in fact in Crichton.

Crichton goes berserk, and almost everybody in the room jumps him. Zhaan staggers back, gasping, "Oh, no," upon discovering that the virus has left Crichton.

Seconds later, everyone is frantically pointing guns at each other. The virus is in one of them, and nobody knows who it is.

It's chaos until Crichton shouts for quiet. He quickly learns that the virus can't infect anybody twice, which makes him and Chiana safe. Larraq, Thonn, D'Argo, Zhaan and Aeryn could all be the host.

D'Argo suggests that Zhaan try to develop the antibody she spoke of -- it's a long shot, but it's all they've got.

Everyone shuffles carefully down to the transport hanger, guns drawn. Crichton can't keep his eyes off Hassan's body while Zhaan works. When the antibody is ready, Zhaan goes first. She's okay.

Aeryn follows, then Thonn, which leaves D'Argo and Larraq. They're eyeball to eyeball, with every gun pointed at them. One of them is the host -- but who's going to be tested next?

In the end, Crichton resorts to "eeny meeny miney moe." When D'Argo tests negative, Larraq -- now revealed as virus-possessed -- makes a run for it.

After a chase through the corridors, Larraq grabs Aeryn, shoots Thonn, then stabs Aeryn when Crichton and D'Argo won't let him go free. He flees to the transport pod, which launches, leaving a trail of cesium gas leaking behind it.

Crichton rushes to the bridge and orders a starburst as Moya crosses the cesium trail. The spark from the beginning of the starburst ignites the cesium gas, which burns its way to Larraq's ship and explodes it. The virus is finished. Rygel and Aeryn will recover -- Larraq's knife missed Aeryn's heart, though as Aeryn tells Crichton, "It was closer than you think."