7th episode of second season, 31th overall. Written by Charles Woodgrove. Directed by Val Guest. Starts 892 Days After Breakaway. Filmed concurrently with "The Mark of Archanon".

Summary

John and Maya start exploring a verdant planet, but on picking a flower and berries, the world erupts against them, as they are accused of killing members of a community of sentient plants. The Alphans are put to a trial by combat against three aliens accused of similar crimes, who have each been given an ability to even their odds against John and Maya. The Alphans alternatively try to flee, talk to, and defend themselves against the aliens. Two of the latter die, but the third captures Maya in an alternate form, trapping and endangering her life. Koenig faces down the final alien and prevails, sparing the alien while the Judges call for Koenig to kill him. Koenig refuses, tossing back that, in effect, the Judges could have warned aliens so as to avoid such incidents, and really just wanted to see death. The other plants protest against the Judges, and the Alphans and final alien are set free.

Plot

John, Tony, and Maya fly in Eagle 1 to a planet. The Eagle develops a fault at the last minute of flight, and John decides to have it land anyway, for him and Maya to explore while Tony returns with a new Eagle.
Maya finds edible plants, so John picks some berries and Maya a flower -- and the world erupts against them. They are accused of murdering members of a community of sentient plants, and despite protests of ignorance, are sentenced by the Judges of Luton, to trial by combat against three aliens, who did similar as the Alphans, and are ready to fight. Koenig shoots one with a stun gun, to no effect, and Alphans flee. The Alphans try to contact Alpha, but this is blocked by the Judges. John starts considering other weapons, like a bow and arrow, or spear.

The Alphans try to communicate with the aliens, but the latter are not interested, and during that, John and Maya also witness the first ability: sheer strength (this alien is referred to as Alien Strong in the credits).
Tony reaches Alpha and exchanges Eagle 1 for Eagle 4, but Helena and Yasko cannot find the planet for him to return to.
The Alphans cross a river, which the aliens do not wish to follow, and try to reach Alpha again, but still only reach the Judges. John asks why the must kill, to be informed it is the rules of Luton. The judges announce the aliens have each been given an ability -- without revealing what.
Maya becomes a kestrel and takes to wing to watch the aliens. One disappears and reappears on the other side of the river (credits thus refer to him as Alien Transport). The alien attacks Koenig, until Maya gets across the river, tries divebombing the alien, but switches tactics -- and form -- to a lion. The alien retreats, but falls into the river and drowns, despite Alphan desire to communicate.
Koenig's shoulder, however, is injured. Maya tends to him, but the remaining aliens find a log to float in the river to cross it, and John and Maya are forced to flee again, John taking the length of rock Alien Transport was using as a weapon.
Tony, meanwhile, is still looking for the planet.
John and Maya start finding dinosaur skeletons, and have also realized the plants have killed off any noticeable animal life.
Maya again takes kestrel form, and then reports she can only see one alien, not realizing the other alien can turn invisible (Alien Invisible). John, meanwhile, has started fashioning a bolo. Not seeing any immediate threat, they talk a little while, until the realize they are being approached by Alien Invisible. John has Maya search for scent; she becomes a dog, and finds the alien, who picks up a rock against her, but then falls backwards down the embankment, to his death.
Tony requests a refueling Eagle.
John has become feverish, the wound infected, and suffering a nightmare. Maya turns into a kestrel again, taking a swatch of cloth to gather water to clean John's wound, but Alien Strong captures and cages her, and uses her and her cries as bait to draw out Koenig. She cannot revert in a cage, and has a metamorphic limit, after which she'll be "crushed" (the rest of her mass returning in a confined space?).
John tries pleading an exchange with the Judges, to no effect, and he tosses his commlock aside and finishes his bolo.
Refueling Eagle arrives at Eagle 4; Tony refuses relief pilot.
John goes down the hill with bolo and rock spear, with difficulty. John and Alien Strong are granted the ability to communicate, and the latter states regret but necessity to kill the Alphans, so he can be free. John uses the bolo, and Alien Strong is injured, but John refuses to kill him, and accusses the judges of being the criminals for not preventing the original crime, and for wanting to see death. Alien Strong is released as the victor, but the other plants are already protesting against the Judges based on Koenig's words, and the Judges let the Alphans go.
The planet appears right in front of Eagle 4, Tony almost crashing as a result. He finds John and Maya, and they leave.

Details

The three adversarial aliens are all of different species.
Alien Invisible, while approaching John and Maya stealthily, uses its ability a couple times. He(?) is capable of hiding its rock weapon as well; but at one point, this does not happen, either because he holds the weapon too far away from himself that time, or (less likely) the power is fading.
Alien Transport apparently has excellent eyesight as well.
Alien Strong was apparently the de facto leader of the three.
The aliens (especially Strong?) are shown to be good trackers. Koenig is aware of such tracking skills and warns Maya to keep to hard ground. It appears John has learned wilderness survival skills at some point.
Earlier, Alien Strong yanked lengths of rock out of a hillside to use as a weapon. One is used against Koenig by Alien Transport, injuring his shoulder, before Maya intervenes. An infection later starts taking hold, leaving Koenig feverish. Koenig insists on carrying this weapon around for awhile.
At a quiet moment, John and Maya get into talking about their respective pasts. Maya states that Psychon was a happy place, rich in resources and lacking in strife. that some ships left Psychon, a thousand (?) people at a time (or at least 1000 on the first ship). John knows she has a (presumably older) brother, and she states that both he and their father were on Psychon's High Scientific Council. She also indicates her mother had died some years before, and her grave was one reason why Maya thinks Mentor refused to leave Psychon.
John reveals that he no longer had parents, brothers, or sisters, and that he was married to Jean but that she died in an awful war in 1987. Maya is shocked about the war. When Maya asks what Jean was like, he states she was like Helena.
Helena is in temporary command of Alpha for most of the episode. Yasko is her primary aide in Command Center at that point. Yasko is on watch at some points.
The remains of dinosaurs (or similar) litter the planet. Some are grouped along the rim of a canyon, as if to make a last stand against the planet.