Season 4, Episode 22:

Bad Timing

Braca's command carrier catches up with Moya and demands the release of Scorpius, which Crichton and the others orchestrate in such a way so that the command carrier has to wait around to collect Scorpius (and Sikozu, who refuses to leave Scorpius) while Moya makes her escape. Braca also has a message for Crichton: a Scarran Stryker has been dispatched to the wormhole that leads to Earth. Crichton believes this is because of his slip-of-the-tongue to Staleek back on Katratzi, when he admitted that crystherium grows in abundance on Earth, and now Staleek plans on conquering the planet in order to harvest enough of the flower to support the Scarran invasion of the galaxy. Scorpius offers a deal: if Earth declares an alliance with the Peacekeepers, the Scarrans will (probably) call off their attack so as not to risk starting a war. Crichton declines, preferring to figure out a solution on his own. As this is going on, Crichton and Aeryn begin to question the future of their relationship again, commenting on what happened the previous year and all their "bad timing".

By the time Moya has reached the wormhole to Earth, Crichton realises that the only way he can protect the Earth is to seal up the wormhole, cutting himself off from his home forever. He decides to go ahead with it, knowing there's no other option, and Pilot agrees to be temporarily disconnected from Moya so that he can operate a transport pod in order to perform the very difficult and pinpoint flying necessary for collapsing the wormhole. Crichton, Aeryn and Pilot head through the wormhole to Earth and park on the moon while Crichton takes care of one last piece of business: visiting the flag that his father placed there decades ago, taking the Crichton family photo pinned there and leaving his tape recorder. And on Earth, Jack Crichton receives a phone call:

With time running out, the transport pod takes off and Pilot begins the manoeuvre under Crichton's instructions. They have to fly the pod into the apex of a "bubble" that forms just prior to the opening of a wormhole, which will collapse the wormhole behind the pod as it flies through. Just as the Scarran Stryker starts heading down the wormhole to Earth, the transport pod comes up the other way, collapsing the wormhole behind it and destroying the Stryker.

To recuperate, Moya lands on a water planet and the crew take some R&R. Crichton and Aeryn row out onto the ocean, a little way out from where Moya is floating, so that they can clear the air and sort out their relationship. Aeryn reveals that when she was on the command carrier, she went to the medical unit and had her pregnancy released: she and Crichton are having a baby. Crichton is overjoyed, and even more enthusiastic than before to get down on one knee and propose using his mother's engagement ring. It's a real, honest-to-goodness happy ending...

...until a ship flies overhead, reporting to his commander that intruders have been sighted on the planet. Realising what's about to happen, Crichton and Aeryn kiss as the ship swoops over them and fires its weapon. The blast turns the pair into millions of tiny crystals that spill not only across their boat, but over the side and into the ocean, leaving only the engagement ring intact.

Roll the Silent Credits.

Tropes present in this episode include:

• Big "NO!": D'Argo gives a gut-wrenching one after seeing what happens to Crichton and Aeryn.
• Blind Seer: Chiana again uses her visions and again loses her sight, only this time it doesn't come back. In the mini-series, her eyes are replaced.
• Character Development: Back at the start of the series, D'Argo had an intense distrust of Peacekeepers. Now he's the one suggesting to John that the Peacekeepers would honour their agreement if they allied against the Scarrans. . . and then proceed to exploit and enslave humanity just like they have everyone else.
• Cliffhanger: John and Aeryn, who had just gotten engaged, are seemingly killed by a weapon that turns them into crystals.
• Continuity Nod: Stark recalls the time he was joined with Talyn during "Meltdown".
• Dangerous Forbidden Technique: In order to make it to Earth's wormhole before the Scarrans, Pilot convinces Moya to perform an extended starburst, which makes the crew feel extremely nauseous.
• Drunk On Power: Stark's attempts to soothe Pilot after he's been reconnected to Moya quickly becomes a ramble about how well Stark himself did piloting her, which becomes more and more unhinged until Noranti knocks him out and tells him to rest with the same soothing words he'd just told Pilot.
• Ending with a Scream: Ends with Crichton and Aeryn getting engaged, only for an alien ship to swoop in out of nowhere and blast them into crystals that tumble into the ocean, with the episode fading out to the sounds of D'Argo howling in rage and grief.
• Erotic Asphyxiation: Scorpius chokes Sikozu with a studded leather belt while initiating sex with her in front of Braca.
• "Eureka!" Moment: Aeryn mentioning that "It's always about time" after Crichton says they never have enough makes him realize that the key to closing the wormhole is timing.
• Flashback Within a Flashback: The episode begins with John flashing back to an earlier discussion he had with Scorpius while he discusses it with Aeryn, which is then itself revealed to be a flashback as John and Aeryn tell D'Argo and Chiana, respectively, about that discussion.
• Genre Savvy: As Crichton and Aeryn talk in the boat, D'Argo and Rygel are observing from command and describing the scene to the blinded Chiana as best they can. When Crichton gets down on one knee to propose to Aeryn and puts a ring on her finger, Chiana is the only one to understand what it means because she watched a number of Earth movies.
• Heroic Sacrifice:
  • So that he, with his superior time perception and precision, can collapse the wormhole, Pilot allows himself to be painfully cut out of Moya at risk of his life.
  • So that Stark can perform the tasks necessary to keep Moya alive from Pilot's control panel, Chiana uses her bullet-time-vision to memorise the necessary control sequences, going permanently blind as a result.
• How Many Fingers?: When it seems certain that Chiana's sight isn't coming back, Rygel holds up his hand and asks her how many fingers he's holding up. Unamused, Chiana responds by biting them.
• I'm Not Doing That Again: On the boat, Crichton discusses how he and Aeryn left their relationship up to the coin toss from last season. Aeryn says she doesn't want to do that again, but Crichton tells her to call it in the air. He tosses the coin in such a way that it would absolutely fall in the water, demonstrating he doesn't want to go through that mess again, either.
• Imagine Spot: This time they really take the cake with Crichton and Harvey 2.0 hunting for Easter eggs while dressed in fluffy bunny suits.
  Harvey 2.0: Curious holiday, Easter. Religious leader dies, comes back from the dead, and you end up celebrating like this!
  (Crichton grabs Harvey and tries to throttle him)
  Crichton: This is not...the time...to be messing...with ME!
• It's All My Fault: Why Harvey actually hopes Crichton finds a way to save Earth. He doesn't want to reside in the mind of the guy blaming himself for the Scarrans conquering Earth.
• I Thought Everyone Could Do That: John mentions that nobody can see the pressure bubble that forms just before a wormhole opens. Pilot reveals that he can see it, and is surprised that apparently nobody else can.
  John: You can see the bubble?
  Pilot: Yes. Can't you?
• Jerk with a Heart of Gold: It's Rygel who convinces Pilot to help with Crichton's plan.
  Rygel: You should do it.
  Pilot: Would you?
  Rygel: No, but I am not you.
• Manly Tears: D'Argo breaks down weeping in the end after Crichton and Aeryn are crystallized.
• Nice Job Breaking It, Hero!: The Scarrans are threatening Earth because of what Crichton told them two episodes earlier.
  "They're gonna go because I told them their flowers were there."
• Not Named in Opening Credits: Kent McCord as Jack Crichton.
• Oh, Crap!:
  • When the transport pod and the Scarran Stryker are about to collide inside the wormhole, both sides have this reaction. They wind up passing through each other, though.
  • The Scarrans immediately afterwards:
    Pennoch: "Emperor! Crichton has turned the wormhole against us! WE WILL NOT--!"
• Opening Shout-Out: Recording his final message to Earth, Crichton quotes the monologue from the show's opening with a few minor tweaks.
• Previously on…: A Blipvert cramming 87 episodes into 33 seconds.
• Sadistic Choice: Saving Earth either means facing the Scarrans alone in a Hail Mary situation, accepting Peacekeeper protection (and the likely chance they'll conquer Earth themselves someday), or finding a way to collapse the wormhole and cutting himself off from Earth, potentially permanently.
• Shout-Out:
  • Crichton and Harvey 2.0 in bunny suits is likely a nod to the original Harvey, who took the form of a giant rabbit.
  • The bomb strapped to Scorpius has "Dear John" written on it, which as in the previous episode is a reference to Doctor Strangelove.
  • In a moment of self-doubt regarding his ability to close the wormhole, Crichton tells Chiana, "I'm not smart enough. I'm not fast enough. I am not alien enough. And you know what? There are people in the universe who don't like me."
• Silent Credits: The end credits roll in silence.
• Skyward Scream: Albeit one of the happier examples of this trope.
  Crichton: WE'RE GONNA HAVE A BABY!
• So Proud of You: Jack's final words to Crichton.
• Sudden Downer Ending: Everything seems to be wrapping up nicely...and then a security ship flies in out of nowhere and fires on John and Aeryn.
• Supreme Chef: Scorpius thinks so of Noranti, as after he's had his first meal back aboard the Command Carrier, Scorpius requests that Braca abduct her the next time they run across Moya.
• Thrown Out the Airlock: At the beginning of the episode, no longer trusting Scorpius and Sikozu, John forces them into spacesuits and ejects them from Moya (trusting that Braca's Command Carrier will pick them up).
• Trapped in Another World: Chricton is forced to permanently strand himself in the Uncharted Territories by collapsing Earth's wormhole.
• Why Did It Have to Be Snakes?: Pilot has to confront his fear of wormholes to help out.
• Written-In Absence: Rebecca Riggs was unable to make an appearance because of her wedding, so Grayza is mentioned as being sedated while confined to quarters.
• You Can't Go Home Again: Permanently this time. To protect Earth from the Scarrans (and the Peacekeepers), Crichton and company are forced to collapse Earth's wormhole. While Earth is still reachable by conventional FTL, that's still a journey of 60 years at top speed (as Scorpius previously calculated).
• You Need to Get Laid: While Crichton is struggling to work out the solution to closing the wormhole, Chiana suggests it might come to him if he took a break for sex. Crichton asks if she means with her or D'Argo.