While at a Peacekeeper memorial, Crichton and the crew are pulled back in time into a great siege between Peacekeepers and the Venek Horde. As they try to stay alive and get back to their own time, they realize that every action changes the course of history-with devastating effects on the future.

Although Scorpius' neural chip has been removed, Crichton feels he has no reason to live - Aeryn is dead, his power of speech is gone, and the Scorpy clone remains in his mind. What's more, the crew of Moya discover they have more than just Crichton and Scorpius to deal with... lurking in the Medical Facility is a murderous Scarran.

While at a Peacekeeper memorial, Crichton and the crew are pulled back in time into a great siege between Peacekeepers and the Venek Horde. As they try to stay alive and get back to their own time, they realize that every action changes the course of history - with devastating effects on the future.

The Peacekeeper Retrieval Squad lead by Aeryn's mother, Xhalax Sun, traces Talyn to a Jungle Planet where the gunship is recuperating. When Crichton, Aeryn and Crais divert the squad away from the gunship, they surmise that Talyn might not be the Peacekeepers' only target. Aeryn realizes that the pursuit of Talyn will not stop until Xhalax is dead.

An Ancient - again taking the form of Crichton's father Jack - appears on Talyn and accuses Crichton of sharing wormhole stabilizing technology with the Charrids, a vicious race allied with the Scarrans. With a Scarran Dreadnought on the way, Jack must unlock the wormhole technology in Crichton's brain to build the ultimate weapon - but must first confront the evil Scorpius Clone in Crichton's mind.

D'Argo and Rygel meet with Scorpius and Braca to negotiate Crichton's safe passage onto the Command Carrier. As a safeguard against doublecrosses, Scorpius suggests that Crichton and Lt. Braca wear matching I-Yensch bracelets that synchronize their nerve impulses so they experience one another's pain. However, before the deal is completed, two heavily armed crazies burst in and hold up the diner.

Crichton has been duplicated into two identical Crichtons. Moya's crew, trying to buy a healing agent for the injured gunship Talyn, become embroiled in a planet's deadly politics. Meanwhile, Aeryn discovers that her own mother is leading the Peacekeeper Retrieval Squad sent to recapture Talyn.

The Peacekeeper Retrieval Squad lead by Aeryn's mother, Xhalax Sun, traces Talyn to a Jungle Planet where the gunship is recuperating. When Crichton, Aeryn and Crais divert the squad away from the gunship, they surmise that Talyn might not be the Peacekeepers' only target. Aeryn realizes that the pursuit of Talyn will not stop until Xhalax is dead.

Talyn draws dangerously close to a star, pulled by a mysterious force. Two alien beings appear on board: the timid Sierjna and her captor, Mu-Quillus. Mu-Quillus is responsible for the radiation pulses that are compelling Talyn to fly into the sun. Stark makes a pact with Sierjna to free her spirit from Mu-Quillus, but his quest puts the rest of the crew in peril.

Crichton ekes out a quiet existence alone onboard Elack - an old, dying Leviathan. But the peace ends with the intrusion of a female alien, Sikozu, and a squad of pirates intent on harvesting Elack's neural tissue. Reunited with former shipmates Chiana and Rygel, Crichton fights to save his new home from the pirates and their vicious pet - the Brindz Hound.

Crichton predicts a wormhole's appearance near Moya, but just then a giant space plant captures the Leviathan. D'Argo attacks the plant in his ship, sending it into Moya's conduits, making it even more difficult to kill. Finally, an agent is found to repel the plant, but it exists only in Scorpius's cooling rods.

After correctly sensing that a wormhole is about to appear near Moya, Crichton is sucked down it! Inside, he is confronted by an interdimensional being intent on discovering why Crichton was entrusted with this knowledge. The alien sends Crichton through various "realities" of past events to illustrate the danger of misusing wormhole knowledge.