Episodes 67 - 88
John Crichton voiceover during opening credits:
- "My name is John Crichton, an astronaut. Three years ago I got shot through a wormhole. I'm in a distant part of the universe aboard this living ship of escaped prisoners, my friends. I've made enemies. Powerful. Dangerous. Now all I want is to find a way home, to warn Earth. Look upward, and share... the wonders I've seen."
Set several months after the end of Season 3, Crichton has been living on board an elderly Leviathan named Elack with only his ancient Pilot and the sole remaining DRD (nicknamed 1812) for company. During his time in solitude he has gone a little crazy, but has also managed to unlock key information needed for his own wormhole research. However Crichton soons finds himself with an unwanted companion, an untrustworthy person named Sikozu who is hunted by criminals. The problem is solved with the assistance of Chiana and Rygel who also are on the run from Peacekeepers, as Commandant Grayza has offered huge rewards for the crew's capture. Sikozu remains with them and the group heads to a planet where they reunite with Jool, D'Argo and Noranti. The Peacekeepers, led by Commandant Grayza soon disrupt the reunion and she captures Crichton and forces him to cooperate. Noranti insists that he must be killed and even tries, but the girls overrule her and break out. Scorpius is apparently shot and killed by Grayza in the process. In the end, Elack sacrifices himself to save the crew, leaving everybody to find Moya onboard Lo'La. After some minor problems, the crew returns, finding Aeryn in an advanced state of heat delirium and Scorpius as her doctor, who as a show of good faith offers to remove Harvey from Crichton's head, an offer Crichton takes him up on. Aeryn is later healed, however she makes Crichton promise not to kill him. Crichton confronts Aeryn about the baby, but she reveals that Peacekeeper bodies put any embryo into stasis to prevent officers becoming pregnany during battle campaigns (so while Aeryn is pregnant, no baby is coming). Crichton is upset with Aeryn for keeping so many secrets, and starts to distance himself from her.
Scorpius begins dragging the crew into the galactic politics, insisting that John Crichton and the priceless wormhole knowledge is key to Peacekeeper victory. This is confirmed when bounty hunters attack Moya and the only ones who can save it are Scorpius and Crichton. The relationship between John and Aeryn grows more complicated when Crichton uses drugs to get over her, supplied by Noranti. Moya flees the Uncharted Territories and heads into Tormented Space, a far more dangerous region swarming with wormholes, but also Scarrans.
During a wormhole experiment, Crichton is sucked into a wormhole by an Ancient nicknamed "Einstein" who warns Crichton of the immense danger of wormhole travel and explains the nature of the Ancients and the wormholes by bringing Crichton to various "unrealized realities" where everything is changed. The bizarrest reality had everyone's personalities and to some extent, appearances altered and mixed with others. Crichton eventually emerges from the wormhole... only to find himself drifting in space next to Earth!
The crew follow him, however find out that the wormhole has deposited them in 1986. With the information from Einstein, Crichton and the crew land of Earth to prevent Jack Crichton from flying on the doomed Challenger mission. They then go through the wormhole again and return to the proper time, reuniting with Moya and Sikozu in orbit of Earth.
Grayza boarded Moya while the crew were in the past, but left when she found no-one aboard (as Scorpius and Sikozu had gone into hiding). However she left behind a Skreeth to wait for Crichton's return and get the wormhole knowledge from him. Braca is also revealed to be a spy for Scorpius, having remained loyal to his former commander.
Crichton reunites with his family and friends, while the other members of Moya's crew are kept under observation and isolated from the majority of Earth's population. Crichton offers to take 500 people from Earth aboard Moya, however doesn't know if he'll go through with it despite Jack and Moya being willing. When Skreeth kills DK and his wife then attacks Crichton and his family, the crew of Moya decide to leave and Crichton his father and his sister farewell before heading back through the wormhole with the others.
Aeryn discovers the drugs Crichton has been using and is furious with him, however he reveals in secret that he has only been acting so strange to stop Scorpius from going after Aeryn to get the wormhole info, as John knows he would hand it over if her life was in danger. The two then secretly begin a relationship.
The crew go on two separate missions in groups; the men go to a mental training facility when D'Argo encounters his wife's murderer and former brother-in-law while Scorpius gets information about Skreeth while the woman go to a Leviathan carcass to buy a device to have Moya register as a Scarran ship. While there they discover Grayza meeting with top-level members of the Scarran government (including War Minister Ahkna, the second-in-line to the Scarren Empire) for peace talks. Grayza offers Ahkna Luxan space despite the fact the Peacekeepers are supposed to be protecting the Luxans. Ahkna agrees however once the treaty is signed she betrays Grayza and attempts to kidnap her. Aeryn, Chiana, Sikozu and Noranti unwillingly set Grayza free before fleeing to Moya.
Back aboard, the crew finds the Scarrans are able to track them however they can find so sign of a homing beacon. Aeryn can't seem to recall some information, and Crichton realizes she's a spy and shoots her. It's revealed this Aeryn is a bioloid (a near perfect duplicate), with the real Aeryn having been captured by the Scarrans during a brief time she was separated from the others. The crew know that the Scarrens were planning to take Grayza to a place called 'Katratzi' but have no idea what or where it is. However Crichton insists that he's heard Sikozu mention it, but she claims to have never heard of it.
As searching for Katratzi leads to one dead end after another, Crichton retreats into himself and watches an intercepted documentary about the crew's time on Earth while he and everyone else accuse Sikozu of withholding information. The documentary, through a coincidence, makes Crichton realize that when he heard Sikozu mention Katratzi it was actually the Sikozu from the Unrealized Reality he visited. Knowing he can't make it alone, he makes Scorpius a deal... if he helps get Aeryn back he can have the wormhole knowledge. Travelling to the Unrealized Reality, the two find out that Katratzi is a hidden base and the seat of Scarren power. Getting its location, the crew resolve to rescue Aeryn, who is being tortured by the Scarrens (which find that the foetus she's carrying contains wormhole knowledge in its DNA).
- Main article: Season 4 credits
- Note: Despite the production numbers, according to the DVD featurette "Save Farscape", the final episode of the series to be filmed was "A Constellation of Doubt", as word of the show's cancellation arrived during production of the episode, which was the last episode filmed for the season.
- Editor's Note: All Commerce Planets will be numbered according to chronological order. Some planet names were fabricated for classification purposes and are labeled with a *.
- Commerce Planet 04
- Commerce settlement
- Scarran border station
- Season 4 saw the addition of Raelee Hill as Sikozu, along with the ongoing appearance of Melissa Jaffer as Noranti (who was introduced at the end of Season 3). Despite both characters, and actresses, being involved in more episodes of the series than Paul Goddard and Lani Tupu were in Season 3, their names never appeared in the opening credits, only as guest stars (unlike Goddard and Tupu, who were featured in the opening cast credits).