Dek (Dimitrius Schuster-Koloamatangi) was a Yautja (i.e., predator) who had not yet earned his cloak (i.e., the device that allows them to go invisible). He was training with Kwei, his older brother, who generally got the better of Dek. When their father arrived, he was irritated that Kwei had not killed Dek. Dek was small for a Yautja and viewed as a weakling that should be culled. To prove himself, Dek went to the planet Genna to slay the supposedly unkillable beast, a Kalisk. He crashed on Genna, losing most of his weapons before his hunt even began.
Thia (Elle Fanning) was a synthetic from the Weyland-Yutani Corporation who had been dispatched to Genna to study the flora and fauna. Synthetics had been sent because the planet was quite deadly. It hadn't done her any favors either, as she had been torn in half and her upper body was stuck in some giant vulture's nest. Luckily, she spotted Dek and offered to help him out. He wasn't keen on this but his situation called for desperate measures. As she was just a machine, he labeled her a 'tool' and carried her along as a backpack.
Bud was a critter native to Genna though unknown to Thia. She had an armored hide that was sort of like an armadillo and would travel quickly by rolling in a ball. When unrolled, she looked monkey-ish. She attached to Dek like a stray cat looking for a meal. Soon, Bud - named such by Thia - was an ally.
Elle Fanning has a dual role. A second synthetic, Tessa, proves to be far less empathetic and has little interest in the friendships Thia has developed on her bizarre odyssey with an alien hunter and indigenous monkey-dog. She does an excellent job of making them different characters as Tessa has dead eyes and a blank expression while Thia is chatty and upbeat.
The action is often ridiculous and way over the top. Dek might swing from tree to tree like Tarzan, fling his plasma sword so that it slices a beast in half, assemble a collection of native bits and bobs into a makeshift battlesuit to rival scores of armed synthetic soldiers. How does Dek communicate with the acid-spitting snake on his shoulder so that it fires at targets? Sure, it's a clever variant of the shoulder-mounted laser-aimed cannon that is a staple of Predator movies, but how does the snake know when to spit? Likewise, Thia proves to be a serious combatant, whose separated body operates in tandem to overcome enemies. Let's not forget Bud, who proved to be quite adept at ripping synthetics limb from limb, mostly off-screen and with an unseemly grin.
The big drawback is that the villains are stupid and not equipped to defend themselves. Where are the motion trackers that figured so heavily in Aliens (1986)? Not on this base. Why are the synthetic soldiers so fragile and bad at soldiering? Why did Tessa abandon her primary mission to go hunting for Dek? You are minutes from success and mostly leave your top priority unguarded. Yeah, good plan.
Good popcorn fun!