A weary Captain Boon returns to Fort Hope from a mission, only to be quickly summoned by Commander Chennault. She wants him to dispense some words of wisdom and encouragement to some freshly arrived ranger recruits. She's less than happy with the world-weary advice he gives. Boon goes to his quarters, where he surprises his young daughter with a doll for Christmas. His wife greets him warmly, but the live Christmas tree she grew is falling apart. Boon promises to spend the next two months of leave with her, but is immediately interrupted by a call from Chennault. A woman looking for Boon has crashed on the far side of the planet. Both Boon and his wife are unhappy as he leaves for the medical center.
The woman says their transport was attacked by Banshees near Skaarab. The planet's second sun will rise in 38 hours and fry the survivors. She hands Boon a Space Rangers badge, which identifies the owner as Decker, a former ranger court-martialed for risking his life and crew to save Boon once. Chennault refuses to authorize the mission. The planet is sacred to one of Earth's allies; even orbiting it would be a grave violation. Boon eventually talks her into it.
On Boon's order, Mimmer wakes up Zylyn from a hiber-stasis chamber, cautioning it's like waking a grizzly in the wintertime. The groggy and surly warrior agrees to accompany them since it would disgrace him to not go, since the entire planet is a sacred burial ground to his race.
Jojo and Doc are in an arena, sharking the rubes. She intentionally loses her first game, played by waving hands over a table of lighted squares. Then she and Doc place larger bets and she easily bests her male opponent. As they leave with their winnings, the losing bettors fight to get their winnings back. As one snatches money from Jojo's hand, Boon takes it back. He cautions the would-be brawlers not to upset Zylyn, and they back away at the sight of the Grakka warrior. He tells the crew that they're going to Skaarab, which stuns Jojo.
As Boon plans in his office, Daniel Kincaid, fresh from the academy, comes in to volunteer for the mission. Boon doesn't want anyone so green, so Kincaid proves he was the fastest in his class in readying and firing his rifle. Boon isn't impressed, saying speed isn't everything. Daniel convinces Boon he'd be taking a bigger risk by going out shorthanded. They say goodbyes on their way to the launch bay. Mimmer wants samples of the incredibly tough vegetation on the planet. Chennault cautions them not to make trouble on the planet. Boon's wife and daughter say goodbye, with his wife especially frustrated. They get onto the Lizzie, where Daniel is gung-ho about the mission and dismissive of the ship. Doc describes all the injuries he's had over the years and all the mechanical replacements he has. Boon orders launch as Doc turns on Beatles music. They launch down the track and through the gravitron accelerator, the rough ride making Daniel nauseous.
On Skaarab, Decker and Grakka priest Nazzer discuss whether Boon will arrive in time.
The ride in the Lizzie gets worse and Doc can't fix it. Boon orders them to slow down to fix the problem. Jojo notes there's a weight anomoly below decks. Doc searches below and finds the woman who told Boon about Decker. Jojo mumbles that she would have been happier seeing Banshees and immediately gets her wish. Daniel gets into a gun turret but can't hit any of them. Boon takes his place and shoots one, but they're tearing through the hull. One is on the cockpit window. Doc electrifies the skin, driving them off and exploding the one on the cockpit. But Daniel's panicked shooting has cost half their ammunition.
Boon finds Zylyn putting his ring into an escape pod, a sign that he doesn't expect to survive the mission. He presses Zylyn for more information about the planet. Zylyn tells him about the history of the Grakka and how they were a warrior race until a dark lord created the ultimate weapon a thousand years ago, a crystal that could kill with a thought. The priests and warriors defeated the lord and they've worn their repressor yokes around their necks as a gesture of peace ever since. The weapon was buried on Skaarab with powerful safeguards around it, which will likely kill them. With repairs complete, the ship resumes its trip.
In a cave on the planet, men chip away at the wall with picks, stopping when they find a glowing tablet incised with alien text. The priest translates the warning, but one of the diggers doesn't believe it. When he reaches for it, he's thrown back with great force. Boon finally gets in touch with Decker and tells him of their plans to rescue them using parajumpers, small single-person pods that can quickly slide up and down beams to the planet.
When they arrive, Jojo notes that Decker's ship doesn't look like it was attacked by Banshees. Doc is startled by a human skull. When Jojo responds to his scream, ground vines snare and nearly strangle her before the others manage to shoot them off. They still get no response from Decker, so they proceed closer to the burial grounds. Zylyn refuses to go further without a priest. Boon finds Decker's body in the cave, but when he reaches out, Decker grabs him and holds him at knifepoint. His cohorts emerge from hiding. Decker demands their ship, while Zylyn refuses to act against the priest.
Decker visits his prisoners who are held behind a forcefield. He portrays himself as a man Boon betrayed by not testifying in his defense. Boon retorts that Decker was in it for the glory, not to save Boon, and that he sacrificed six men for it. Decker set this trap knowing Boon would not let him down. The priest insists that Decker's men open the glowing door. They run when it starts crackling. The door needs to be opened by the pure of heart, so Decker orders Boon out. But Doc rushes out first. He reaches for the door and is thrown back. But the door vanishes, showing a chamber with a skeleton holding the crystal inside it. Decker again orders Boon out and looks at the crystal with great anticipation. Daniel arrives at the cave mouth, seen only by Jojo. He shoots a stalactite to destroy the forcefield generator below. Freed, the rangers begin taking on Decker's men. Zylyn confronts Nazzer, who demands obedience. But Zylyn no longer respects him with the tomb opened. He throws Nazzer across the cave, where he's impaled on a stalagmite. Boon wrestles with Decker, who gets free. He holds the rangers at bay with the priest's spear then runs into the tomb. He takes the crystal and tries to use it on Boon, but it senses his darkness and kills him instead, collapsing the cave on his skeleton.
Boon returns home in time for Christmas morning and plants his wife's tree in the ground. He's accepted that she intends to leave. As they embrace one more time, Jojo and Doc arrive alarmed. Zylyn has gone after Mimmer. They find Zylyn and demand to know where he is. Zylyn only smiles. Boon suddenly realizes where Mimmer is. He opens the hiber-stasis chamber to find a gel-covered Mimmer inside. He's relaxed and happy. "You guys really gotta try this!"