In outer space, two spacecraft are in the middle of a fierce laser fight when suddenly one of the ships opens a wormhole and goes through it just in time to escape from its enemy. This spacecraft is now coming close to Earth, and on its way it wipes out a satellite. The ship appears to be damaged and the alien, which is from a race known as Predators, gets away in an escape pod before the ship begins falling.
Meanwhile in a Mexican jungle, sniper Quinn McKenna is on a mission to catch some cartel members. The moment he makes his first shot, the Predator ship finally crashes and sends Quinn rolling away. When he wakes up seconds later, he investigates the crash site and comes across some of the Predator's armor.
Suddenly Quinn is startled by his teammate Dupree, who lends Quinn a bag so he can take away the armor. While Quinn is trying on the arm brace, they hear a noise in the trees and see the body of another teammate hanging upside down from a branch. Then the Predator appears too and the soldiers try to shoot it, but it moves too fast and uses cloaking so the shots don’t land.
The Predator shoots back and kills Dupree, but when Quinn comes closer, the arm brace activates and shoots something that knocks out the alien and slices the hanging body in two. All the falling blood makes the Predator visible again, so Quinn grabs his bags and leaves. On his way out, the brace releases a little ball that Quinn catches.
Soon, a special team led by Traeger arrives to take the Predator and anything salvageable from the crash away. Trager’s instructions indicate he’s familiar with this alien race. In the morning, Quinn arrives at a nearby town and makes everyone in a bar leave by showing his gun.
Then he pays the barman to mail his bag to his son’s house. He keeps the little ball, and when he realizes that it can make him invisible, Quinn swallows it with a drink. Meanwhile Quinn's son Rory is in a classroom watching some boys play chess.
He’s got autism, so he’s often ignored by his classmates or made fun of. In the corridor, two older boys set off the fire alarm and everyone panics while Rory has sensory overload and stands back in fear. The two boys go into the classroom and knock over all the chess pieces, they also mock Rory before leaving.
Once the fire alarm stops, Rory notices the fallen pieces and proceeds to put them exactly where they were thanks to his amazing memory. Later at home, the mailman brings Rory the box sent by Quinn. At a park, three special agents approach Doctor Casey and make her come with them, not offering an explanation until they get in the car.
They show her photos of the crashed escape pod and the Predator, telling her that they've visited Earth on other occasions already and that the visits have been increasing in frequency. In the evening, Rory’s mother Emily brings some masks so he can go trick-or-treating, but Rory refuses to go because the bad boys will recognize him anyway. Afterward Rory goes to the basement and opens the package to find the Predator's gear, which immediately fascinates him.
As he inspects the arm brace, it suddenly activates, and Rory starts using it as a computer. Meanwhile Quinn has been caught and is now put through a psych evaluation while Traeger watches, and Quinn can tell they want to keep it all under wraps. Then he’s placed on a bus with other prisoners who behave rather freaky.
They tease him a lot and don’t believe him when Quinn says he’s being silenced because he saw an alien. As the bus leaves, Casey arrives and meets Traeger and his team of scientists. She’s surprised to discover they have all kinds of alien items and most importantly, a Predator that they’re keeping sedated.
After going through decontamination, Casey is allowed to take a closer look at the creature. Traeger explains they’ve nicknamed the race Predators because they seem to enjoy hunting and that recent studies reveal the sleeping one has traces of human DNA on its body. They want to know if someone on Earth did the nasty with an alien, so Casey looks at the files and demands to speak with Quinn.
Soon the bus gets a message that makes it go back. At that moment, the other ship from the chase at the beginning also opens a wormhole and arrives at Earth’s sky, bringing two alien hounds and a Predator that is now reading the signal from Rory’s brace. The army detects the spacecraft’s presence and sends two fighter jets after it, but they have trouble keeping up with the alien technology.
Suddenly at the facility, the Predator wakes up. The scientists try to hold it down, but it’s too strong and quickly breaks free to start killing without mercy. While chaos takes over the room, Casey grabs a tranquilizer gun from a dead guard and steals an alien sample before running away.
The security system won’t open the door without going through decontamination, so Casey must go through the shower first. Meanwhile the Predator realizes its armor is missing the helmet and the arm brace and decides to leave, seeing Casey in the showers on its way out. Since she doesn’t look like a threat and thanks to her the door is open, the Predator ignores her and goes out to the corridor where he grabs a helmet the scientists took from other aliens.
By activating it, the creature can see where its helmet is and finds Rory’s location. While a scientist tells Casey not to let the alien get away, the alarm echoes through the whole facility as the Predator kills every soldier that tries to stop it from escaping. The bus comes to a stop and the soldiers see the Predator running on the roof, finally believing Quinn and making a plan to escape.
The group starts a fight to make the guards come in, then they work together to knock the guards down, take their weapons, and throw them off the bus. Both Casey and the bus start chasing after the Predator, who at that moment sees the other spaceship fly by with the two jets and goes after them. Casey jumps off the roof and lands on top of the bus to shoot at the alien, but she accidentally shoots her own foot instead.
Next Quinn tries to open fire too, but the Predator destroys a tire and makes the bus stop. While the guys look for an alternate vehicle, the two jets keep on trying to shoot down the spacecraft, but it suddenly goes invisible and destroys both jets in seconds. Casey is almost killed by some guards, but the guys have found bikes and rescue her just in time before finally escaping.
The Predator sneaks inside the back of a truck and kills the soldiers as the vehicle leaves the facility too. Not far from there, the other alien finally lands and sends its hounds to search for its enemy. In the meantime, the soldiers hide in a motel room and wait for Casey to wake up.
When she does, she thinks she’s in danger and grabs a shotgun, but Quinn quickly stops her and explains they’re on her side, it was Traeger’s men who tried to kill her for stealing the sample. Casey accepts to work with them and tells them what she knows, which makes Quinn realize the Predator is going after Rory to retrieve its gear. Meanwhile Rory discovers the helmet is on and tries it on.
He sees a clip of how the Predators improve themselves by injecting their bodies with the DNA of other species, which explains the human DNA they found in the facility. Happy with the result, Rory decides to go trick-or-treating with the helmet and the arm brace as his costume. By the time the soldiers arrive at the house, Rory is already gone, so Quinn explains everything to Emily, who lends Quinn a weapon so he can go save their son.
At first the other soldiers don’t want to get in danger again, but after Emily tells them how good Quinn is at what he does, one by one they end up joining the hunt. They agree to split into pairs to cover more ground. Back to Rory, he’s sadly recognized by the prankster duo and they immediately begin making fun of him.
Trying to ignore them, Rory goes to knock on a house and gets no answer, but the owner appears on the balcony and also makes fun of Rory as he throws something at him. This activates the helmet, which shoots a blast that kills the man, blows up his house, and makes the other kids run away. The blast is seen by Quinn and Casey, who drive in that direction.
A very scared Rory drops the helmet and runs to hide in a baseball field, where he finds a dog and immediately befriends it. At that moment, the alien hounds show up, but before they can attack, Quinn arrives and pushes them away with the car. Soon the rest of the team arrives too and while Casey takes Rory away, the guys open fire.
Quinn runs when a hound comes after him, but after a bit of chasing, he manages to blow the beast up by shooting a few grenades into its mouth while the other one is shot to death. Then Casey takes some samples, only to be interrupted by the sudden appearance of a Predator, who grabs Nettles and threatens to kill him to make the group drop their weapons. They do as told, but Quinn quickly grabs his weapon again and shoots at the Predator, making him release Nettles.
Afterward everyone runs to hide inside Rory's school right before the alien blows up the front door. Knowing what the Predator wants, Quinn takes the mini-computer from Rory’s brace. The Predator finds them and grabs Quinn by the neck, so Quinn gives back the device.
Before the beast can react, the alien drops Quinn and falls through the window: it turns out it’s been pulled out by the other Predator. As the humans drive away, the aliens battle each other, and the bigger Predator easily wins by smashing the smaller one into a car and tearing its skull and spine out. The police are approaching, so the Predator looks at the humans’ identities on the device before turning invisible to escape.
Afterwards, Quinn calls Emily to check on her, but government agents are watching her so she destroys her phone to stop them from getting to her husband. Meanwhile Traeger and his guys find the Predator's body, and Traeger determines that the bigger Predator was hunting this one for something he stole. He wants this thing that seems so important, and to find the ship, he realizes he must find Rory.
Back to the group, they’re now hiding in a barn and by looking at the sample, Casey confirms that the Predators are upgrading themselves. Suddenly they hear some noises and discover the other hound has survived the grenades and has followed them here but Nettles doesn’t let them shoot it because it’s behaving just like a dog and it could be useful. Casey tries to communicate with it, but at that moment Traegar arrives in a helicopter, so she throws something for the hound to go after and hide.
The rest of the group also hides while Traeger asks Quinn and Casey where the arm brace is. Since they refuse to answer, the agents hit Quinn while Traeger interrogates Casey. He explains that Predators know the human race is destroying the planet and doesn’t have much time left, so they’re gathering the best DNA before we go extinct.
At Emily’s house, the agents are looking around for the alien gear when suddenly the Predator bursts in. Emily hides while the alien kills all the agents in seconds, then looks at Rory’s desk to discover a map with the location of the ship. That same map is currently being drawn by Rory, and the agent watching over him quickly catches on, so he lets Traeger know.
Immediately Traeger takes Rory away in the helicopter, leaving only a few men to kill the duo. Quinn easily beats two of them up with his expert skills, and when the third one is about to kill Casey, the hound shows up and pukes a grenade. Casey uses the distraction to hit the guy with a chair, then she jumps off before the grenade blows up.
On his way out, Quinn encounters Nebraska beating up the last of the guards. Then they reunite with Casey and when they wonder how to escape, the rest of the team shows up in a helicopter to take them away while the hound follows them on the ground. Soon everyone arrives at the site of the other ship.
Traeger makes Rory unlock the door and they come inside, where Traeger orders his men to take everything. Suddenly one of the agents is pushed away and it’s revealed that Quinn has been following them by using the cloaking device from the ball. After killing or knocking down all the guards, Quinn captures Traeger and brings him outside, where the rest of the group is taking down a few agents to surround the place.
Suddenly, one of Quinn’s friends is attacked by the Predator, but before dying, he manages to shoot a flare. The distraction allows Traeger to hit Quinn and run away, which causes a gunfight to start between Quinn’s men and Traeger’s. Quinn hides with Rory and gives him the cloaking device while the Predator jumps in and kills most of Traeger's men, causing a jeep to turn and explode nearby.
Then it enters the ship and sends out a message through the speakers that makes everyone’s ears hurt before it begins translating. The alien explains it came to destroy the ship and nobody can have it, it also wants “McKenna” as its prize because he’s the best warrior of the group. The Predator ends the message by setting off a timer to destroy the ship.
Quinn and Traeger agree to leave their fight behind to work together. Traeger tries to take some alien things before leaving, but the hound immediately stops him. Both teams hide in the forest and the Predator leaves the ship right before it finally blows up.
Seconds later, the humans hear a weird noise and suddenly a Predator weapon flies in, cutting an agent’s arm. Traeger shoots his the guy because he considers him useless now, so the Predator steals the body to feed. The teams begin to back off as they open fire and two of Quinn’s friends decide to play bait.
The noise attracts the Predator, who jumps in and begins killing humans as everyone shoots at it to no avail. Traeger tries to kill it with its own weapon, but it ends up blowing his head off instead. Eventually the Predator catches on fire but it doesn’t bother it much, so it hurts the two friends before they push it down the hill.
Because their injuries are so severe, the duo won’t be able to survive this so they kill each other to avoid the pain. Soon the Predator comes back and pushes Casey and Quinn away to drag Rory, who is the real McKenna he’s been asking for all this time because he’s next in the evolutionary line. As the alien takes Rory away in his ship, the boy drops the little ball in the process.
Quinn, Nebraska, and Nettles hop on top of the spacecraft as it takes off and pushes Casey away before she can also jump. Inside, Rory sees the Predator activating the force field and warns his dad through the comms, so he dodges it quickly. However Nebraska is left outside of it and Nettles loses his legs before falling to his death.
Next Nebraska decides to self-delete into the ship’s turbine to make it start falling. Quinn uses the protection of the force field to sneak inside, but he can barely shoot the Predator a few times before the ship starts shaking and he falls away, only surviving because his leg gets stuck on some rope. The spacecraft finally crashes and the Predator comes out to start fighting Quinn, but the human isn’t strong enough to end such a strong beast.
When the Predator is about to end him, it’s revealed Casey is using the cloaking device and jumps on the Predator from behind to shoot it in the head. After she falls, Quinn pushes the alien off the edge, where it loses its arm when Rory activates the force field. Casey catches the arm and throws it at Quinn, who immediately shoots to knock down the Predator, ending it with a few shots to the head.
Afterward, Quinn takes several items from his fallen comrades, and he and Rory take a moment to memorialize the men. Sometime later, Quinn visits a new government facility that is preparing to fight aliens in the future with the help of Rory’s knowledge. They finally found the mysterious item that the Predator had stolen and was being chased for: it turns out to be a powerful armor that Rory says is called the “Predator Killer”.
It seems the alien was bringing it to Earth so humans could fight against its own race. The armor wraps itself around a scientist and looks like it may open fire, but it soon turns off and goes back to normal. Quinn then declares that this is his new suit.
