Summary
Dek is a Yautja runt from the planet Yautja Prime. Seeking approval from his father, clan leader Njohrr, Dek plans to hunt the Kalisk, an apex predator on the "death planet" Genna, feared even by Njohrr. Before Dek can leave, Njohrr arrives and orders Dek's brother Kwei to kill him, deeming him too weak for the clan. Defying the order, Kwei activates his ship to transport Dek to Genna, fighting Njohrr only to be defeated and lose an arm; Dek watches helplessly as Njohrr executes Kwei.
Upon crash-landing, Dek faces numerous dangers from Genna's flora and fauna, losing almost all of his gear. He reluctantly allies with Thia, a damaged Weyland-Yutani Corporation android, whose team was destroyed by the Kalisk. Thia offers to help Dek track the Kalisk. Later, they are joined by a friendly creature that Thia names Bud, which marks Dek with her saliva while they are camping out of gratitude to Dek for saving her from a wild beast and feeding her. Dek later reveals to Thia that his father killed Kwei, prompting Thia to teach him about the wolves on Earth, telling him that the alpha wolf takes care of the pack. Dek however remains adamant about being 'the alpha who kills the most.' Meanwhile, Thia's "sister", Tessa, is retrieved by Weyland-Yutani androids and repaired at their main base, where she is threatened with decommissioning if she fails her mission, and is told of Dek's presence on Genna and that Thia is with him. Joined by a Weyland-Yutani team, Tessa begins searching for Dek's group, stumbling across his crashed ship and finding his lost equipment - including cryogenic explosives.
After discovering the remains of her team, Thia attempts to repair herself, revealing the Weyland-Yutani team is on the way, as they aim to capture the Kalisk, and urges Dek to flee, saying he cannot kill the Kalisk. Feeling betrayed, Dek challenges the Kalisk alone with only his sword. The two fight, and though Dek manages to sever its head, the Kalisk regenerates itself and subdues him. Unexpectedly, it spares him after smelling him, but the Weyland-Yutani team arrives and captures them both.
Tessa congratulates Thia on the successful mission, then begins experimenting on Dek, but Thia intervenes, claiming that they can be more than what Weyland-Yutani demands from them. Seeing Thia's emotions as weakness, Tessa slates her for deactivation and orders her boxed up. Thia helps Dek escape the transport vehicle, tricking one of the guards with an explosive toy that cost Dek one of his fangs as a child. After venting out his anger over Kwei's death and realizing the meaning of Thia's words to him about the wolf, he decides to rescue Thia, creating improvised weapons out of Genna's natural environment and creatures. While doing so, he reunites with Bud and realizes she is the child of the Kalisk, who had smelled her saliva on him, and decides to rescue the Kalisk as well.
Dek and Bud infiltrate the Weyland-Yutani base, kill most of the guards and free Thia, who reunites with her severed legs as Dek reveals to her that Bud is the Kalisk's child. While Thia and Bud search for the Kalisk, Dek kills the remaining guards before being confronted by Tessa, who pilots a power loader mech and wields Kwei's plasmacaster. The Kalisk, freed by Thia, joins the fight and eventually swallows Tessa alive. After Dek and Bud each share a moment with the Kalisk, Tessa kills the creature with a combination of cryogenic grenades and plasmacaster blasts from inside its body, and prepares to kill Thia for her betrayal. As Thia severs ties with her "sister," Dek stabs Tessa to death and reclaims his brother's plasmacaster, while Bud tears off Tessa's head and spine.
Sometime later, Dek returns to Yautja Prime. He presents Tessa's skull to his father as a trophy and demands his own cloaking device as a reward, but Njohrr denies the request and orders his bodyguards to kill Dek. Quickly dispatching the bodyguards, Dek challenges and defeats his father in a duel, cutting off his arm and restraining him with his own trap. Njohrr attempts to barter for his life by offering Dek a place in the clan, claiming he was wrong about him. Dek rejects the offer, having found his own clan with Thia and Bud. An older and larger Bud bites Njohrr's head off, and Dek takes the cloaking device for himself, which a fully-repaired Thia congratulates him for. Njohrr's remaining clan members suddenly pull out their weapons just as a large Yautja ship appears from the horizon. As Thia wonders if the ship is friendly, Dek grabs his sword and reveals that it is his mother.
Source: Wikipedia (CC BY-SA 3.0)
