Season 4, Episode 13:
Terra Firma
The crew of Moya and the humans start to learn more about one another. As Crichton reconnects with the people in his life, he tries to encourage the people of Earth to unite in their efforts to master space travel and join the larger universe. Unfortunately, the American government is more concerned with learning the secrets of advanced alien technology for its own use, and Crichton's family are aware of just how much he's changed during his time in the Uncharted Territories.
Crichton's debate about whether or not to stay home or return to Moya reaches a head when Grayza's creature stows away on a transport pod, kills several people (including D.K. and his wife) and attacks the Crichton family during Christmas celebrations. The creature is killed, but Crichton realises he can't stay on Earth because he's still being hunted. Before the crew leaves, Crichton says a proper goodbye to his father and receives a gift from his sister: their mother's engagement ring, for him to give to... someone.
Tropes present in this episode include:
- An Asskicking Christmas: The action goes down on Christmas Eve.
- Bittersweet Ending: Earth is safe, but only for now, so Crichton leaves.
- But Now I Must Go: Crichton leaves Earth so it won't be targeted in future attacks.
- Christmas Episode: Amid all the craziness, the Crichtons just try to enjoy the holiday.
- Cliffhanger Copout: The previous episode ended with Crichton pulling a pulse pistol on his father and demanding a Trust Password to confirm it's really him. This episode opens with Sikozu interrupting to reveal she's already confirmed that Jack and the other humans are who they say they are.
- Dropped a Bridge on Him: Minor recurring character DK gets killed off with little fanfare.
- First-Name Basis: John starts calling Jack by his first name over their argument on whether to share the technology with the world.
- Foreshadowing:
- Sikozu gets surprisingly upset when she is asked if she'd be willing to submit to some biological testing. "We're So Screwed" reveals that she's a bioloid, a fact that probably would have been discovered if she agreed to the tests.
- Bobby's recording and interviewing the aliens sets up "A Constellation of Doubt".
- Aeryn learns about the drugs Crichton has been taking—setting up part of the next episode.
- Gilded Cage: Lampshaded by Crichton when, contrary to his fears in "A Human Reaction", the aliens are treated like VIP celebrities.John: (voice-over) I figured Earth would freak out and it's delivered in spades, on time, 30 minutes or less. Uncle Sam is keeping the aliens safe and contained. A waterfront mansion for their personal use, with full security team standing by. It's a cage—but at least it's a gilded one.
- Heroic Sacrifice: Scorpius makes preparations to blow up the wormhole to Earth if Grayza tries to use it. Fortunately, this proves to be unnecessary.
- Human Aliens: Jack notes that he wouldn't be able to tell that Aeryn isn't human.
- Manly Tears: Jack when Crichton leaves.
- Mind Rape: The Skreeth can do this, while assaulting his victims.
- No Doubt the Years Have Changed Me: Both Crichton and his father.Crichton: I look at these pictures, and I recognize the faces, some of the places, but it's not my life. [touches a picture of his mother] I miss her. [touches a picture of Olivia] I miss that chick! [touches a picture of Jack] I miss him, but I can't, I... he's changed.
Olivia: What? He's changed so much that you can't talk to him? You know he says exactly the same thing about you. "He's changed so much, and he's—"
Crichton: I have changed, and I can't tell him why. - Properly Paranoid: Crichton fears telling the world all about his experiences will make the situation even worse.
- Puppeteer Parasite: To contact the Skreeth, Grayza sticks a device on Braca's forehead. It completely suppresses Braca's personality and lets the Skreeth talk through his body. When the device is removed and later when Skreeth is killed, Braca doesn't remember a thing and Grayza tells him they had sex.
- Shout-Out: A green character ruining others' Christmas?
- Stranger in a Familiar Land: Crichton is physically back at home but is forced to admit that his experiences in space, and the changes to Earth culture following 9/11, mean he no longer fits in. When Grayza's tracker attacks his family home he decides it's not safe for him to stay and returns to Moya with the rest of the crew.
- Straw Character: Averted. Jack's initial attitude is in response to 9/11, but he gets to state his side of it and counter Crichton's points. T.R. Holt is far more obstructive, but like a typical bureaucrat rather than a partisan politician.
- The Men in Black: Suited government agents are assigned to keep Moya's crew contained. One of them tries to convince Crichton to give the US exclusive access to his technology. Crichton asks the MIB if the suits come with the job or if he has to buy them himself.
- There Is No Kill Like Overkill: Skreeth meets his end by a blast at close range from D'Argo's ship, which has previously been shown capable of vaporizing a Leviathan.
