The film opens with the voice of an android named Jimmy (Anthony Hopkins) narrating over the history of the Motherworld. The pursuit of power led to the royal family’s conquest until an assassin murdered the king and queen (Cary Elwes and Rhian Rees). A tyrant named Balisarius (Fra Fee), who leads the forces of Motherworld, sends his brutal second-in-command Admiral Atticus Noble (Ed Skrein) into the far reaches of the Motherworld to seek out those who plan to begin a rebellion.
On the planet Veldt, a woman named Kora (Sofia Boutella) tends to her crops before meeting her friend Gunnar (Michiel Huisman) to go to a harvest celebration in their village. The village’s chief, Sindri (Corey Stoll), addresses his people while a hunter named Den (Stuart Martin) has eyes for Kora, though she has no interest in a romantic relationship.
While out with her friend Sam (Charlotte Maggi), Kora sees Motherworld ships descending upon Veldt. The community discusses how to approach the visitors before three smaller ships led by Noble arrive in the village. Noble speaks to Sindri over potential rebels in the land, as well as questioning him over the supply of crops they yield (Gunnar had sold surplus crops to enemies of the Motherworld). After a tense exchange, Noble beats Sindri to death in front of his people, along with another woman. He then demands to Gunnar that the village hand over their grain supply within ten weeks.
Elsewhere in the village, a young soldier named Aris (Sky Yang) appears to take a liking to Sam but must watch as his superiors taunt her. He also briefly speaks to Jimmy, who talks to Sam about Princess Issa (Stella Grace Fitzgerald), daughter of the slain king and queen who perished along with her parents on that day. Jimmy laments how Issa was supposed to usher in a new era of kindness, only for it to be taken away so cruelly.
The villagers debate on how to handle Noble and his men, with some offering to appeal to their humanity. Kora later sees as some of the soldiers harass Sam and attempt to rape her, even as Aris tries to stop them. Kora enters the barn with an axe and proceeds to slaughter the soldiers until the captain holds Sam at gunpoint. Jimmy enters, and the captain orders him to kill Kora, but Jimmy instead shoots him. This is enough to convince Kora they need to fight back since Noble will kill off the villagers when he returns.
Kora leaves Veldt with Gunnar to seek out a group of insurgents called the Bloodaxes who may aid them against the forces of Balisarius. Kora tells Gunnar about how she witnessed the slaughter of her community at the hands of the tyrant when she was a child, and she was faced with an opportunity to kill him when confronted with him, but her weapon was out of ammunition. Instead of killing her, Balisarius had Kora train at the Imperium along with other soldiers under the name Arthelais, turning her into a killer before she deserted them. Despite being groomed into being a mercenary with no emotional connections, Kora had a lover who was killed in battle.
Kora and Gunnar arrive in the Port City of Providence to seek out the man who may lead them to the Bloodaxes. When the two mention General Titus (Djimon Hounsou), a nearby man named Kai (Charlie Hunnam) begins to pay attention. Kora and Gunnar are accosted by a thug who attempts to sexually assault Gunnar before Kora knocks him down. A nearby alien tells Kora and Gunnar about Titus’s whereabouts before the thug returns with back-up. Kora and Gunnar fight and kill them until the main thug has Kora at gunpoint. Kai raises his firearm and blasts the thug in the head before introducing himself as a smuggler and joining Kora and Gunnar.
Kai suggests to Kora that he knows a man who can aid them on their mission. He guides them to a ranch on another planet to find a man called Tarak (Staz Nair), who is being kept prisoner by the rancher, Hickman (Ray Porter), due a debt Tarak owes him. He is told about Kora’s mission, and the three bargain with Hickman that if Tarak can tame a nearby chained-up creature called a Bennu, then Tarak can go free, otherwise, all of them will be indebted to Hickman. Tarak approaches the Bennu and communicates with it. After freeing it, Tarak rides the wild beast. He is granted freedom to join Kora, but as he leaves, he witnesses Hickman poorly handling the Bennu, which ends with the creature killing Hickman by sticking its talon through his chest.
Kai then leads Kora to a cobalt mining planet where they meet a swordsman called Nemesis (Doona Bae). Kai informs her of the job just before she meets a humanoid spider creature called Harada (Jena Malone), who is keeping a small girl captive before preparing to kill her. Nemesis tries to negotiate with Harada but ultimately ends up battling the monster and impales her fatally before saving the girl. Nemesis joins the rest of the crew. The experience makes Kora reminisce over how she spent time as the royal guard for Issa when she served the Imperium. She witnessed Issa bring a bird back to life, and the king had believed Kora being her friend made her feel safe, but Kora clearly feels guilt over what happened to Issa and her parents.
The crew goes to a moon that holds a gladiator arena where Titus is. Once an Imperium general, he now lives disgraced on the streets and works as a prize fighter after his previous failure in battle. While Titus remains ashamed of his past, Kora convinces him to fight back so he can get his revenge.
The crew then goes to the planet Sharaan, where they meet King Levitica (Tony Amendola) so that they can meet the Bloodaxe siblings, Darrian (Ray Fisher) and Devra (Cleopatra Coleman), in the hopes that Gunnar’s previous connections with them may give them a chance at convincing them to join their rebellion. The two have no desire to help until Kora gives them a speech. Darrian then gives his own speech to his clan, with half of them joining him and the other half going with Devra. Noble and his crew, the King’s Gaze, have been tracking the Bloodaxes and later turn up on the scene after the insurgents retreat, and he kills Levitica before laying siege to the area.
Kai guides the crew to a trading post under the guise that he is dropping off goods before setting off for a better life, but he was actually in cahoots with Noble this whole time and was trying to collect the bounties on the heads of Kora and the others. Noble has them captured and reveals he knows more about the crew than they let on. Tarak is actually a prince, while Nemesis killed several Imperium soldiers to avenge her murdered children. When Gunnar is ordered to execute Kora, he instead grabs the weapon and uses it to kill Kai. A battle breaks out between the freed rebels and the King’s Gaze. Darrian gives his life to bring down a ship and save as many of his people as he can. Most of the villains are killed before Kora and Noble have their showdown atop the post’s highest platform. After an intense fight, Kora overpowers Noble and knocks him off the ledge.
The crew returns to Veldt and enjoys their temporary victory, but they are aware that the Imperium will soon retaliate. Kora brings her new friends back to her village, more hopeful for their future than before.
An Imperium ship recovers Noble’s body and starts to revive him. His mind is taken to a realm where he communicates with Balisarius. Despite thinking he will be happy to know about Noble finding Kora, Balisarius is instead angered and demands that Noble bring Kora to him so that he may kill her personally.