In the city of Los Angeles, detective Mark is having time off while grieving for his dead wife
Rose, which has given him a drinking problem. However he has to return to the station when he
hears his son Trent has been arrested for getting in a fight. Officer Garcia convinces the other guy
not to press charges, so Mark gets Trent out and proceeds to scold him thoroughly. Things have been
tense between them since Rose's death and it only gets worse when Trent notices Mark spent his money
on alcohol instead of filling the car's tank. They decide to take the subway instead, and on their
way there, Trent leaves some money for blind hobo Sarge. In the subway, Mark keeps fidgeting with
Rose's ring and decides to hear Trent's side of the story, allowing them to have a soft bonding
moment. Suddenly, the train comes to a stop at the same time a bright blue light appears
in the sky. Mark checks with the transit worker named Audrey, who explains there's been a power
outage and the radio's down. Then something makes the whole underground shake and Audrey receives a
message through the radio saying "don't look at the lights". When the whole train shakes again,
the group decides to evacuate, and as they walk along the railing, they hear mysterious noises
coming from above. Meanwhile Garcia comes out of the bathroom and finds the station empty except
for officer Jones, so they look around and find the bright light outside. Everyone is following
the blue glow except for Sarge, who isn't affected because of his blindness. The underground group
reaches the station and tries to find a safe route to escape, but a woman is desperate to return to
her family and tries to take the stairs outside. Trent follows her to convince her to come back
and both of them end up looking at the light, which makes half of their faces go black. Mark
notices this and closes his eyes to grab his son to keep him here while the light suddenly becomes
a beam that takes away every person that looked at it. When Mark opens his eyes, he discovers
the beam came from a giant spaceship. Afterward, Mark brings Trent back to the subway station and
together with Audrey and the few survivors, they go back to walk through the tunnels. There they
meet with Garcia, Jones, and Sarge, who join the group to look for a safe exit. Garcia also gives
Mark a gun to defend himself. After walking all night, they find a set of stairs with a window
that allows them to see the air force is attacking the spaceship. Jones finally gets a signal on her
radio and asks for help but it's denied because they're about to bomb the city without caring if
there are any survivors left. The spaceship's defenses easily take down the air force,
and as bombs and falling planes start hitting the ground, the tunnel begins to crumble. The group
immediately runs away, but the unknown survivors get killed by the debris. The rest of the group
finds a hole in the ceiling, but when they're about to escape, an alien appears in the tunnel
to attack them. The creature absorbs Garcia before turning on its light to attract Trent again,
and Mark starts shooting at it until it dies. Then he rescues Garcia, who is surprised by the fact he
could breathe inside the creature. Jones wonders if the aliens want them alive, but at that moment,
the creature wakes up and grabs Jones to remove her brain. Mark begins shooting again to give
the others a chance to escape, this allows the alien to grab him by the legs. Thankfully Audrey
has an emergency flare with her and tosses it to Mark, who uses it to make the creature
step back. Afterward he puts it inside the gas tank of a car that fell into the hole,
so when the creature tries to follow the group as they escape, the car explodes and kills it.
Now they're outside they can see the spaceship sending a giant alien after them. The group
begins to run away, but the alien is too close, so Garcia stays behind to buy his friends some time.
Unfortunately his bullets do nothing, and the alien absorbs him with its tentacle. Mark, Trent,
Audrey, and Sarge notice there are helicopters in the area and try to get their attention,
but the giant alien suddenly blocks their way and shoots the helicopters down. Then the spaceship's
lights begin taking the group away, and since it can't take Sarge, the alien picks him up manually.
The giant alien returns to its ship, where it's revealed that this huge creature is actually
a giant robot being piloted by a human-sized alien. Now that the alien is done with the USA,
it moves the ship to begin harvesting other places. Meanwhile Mark wakes up in a room full
of bodies and alien goo. There's another creature there, which is also actually a robot, collecting
people's brains. Mark dodges the tentacles to try to find Trent, and when he shoots at the robot,
the alien captain notices him on his sensors and turns on the beam again. All the bodies are taken
away except for Mark, whose head is grabbed by the robot to try to get his brain. Mark immediately
shoots the tentacle and falls in a current of water that is being expelled from the ship. When
he's about to fall out, his leg gets stuck on the ship's railing, saving him but also getting hurt.
Then Mark climbs back inside and discovers that the human brains are put inside more robots to use
them as soldiers; the only actual living creature here is the captain. Unaware Jarrod is following
him, Mark makes his way further inside, coming across rotting bodies and eggs hanging from the
ceiling that seem to have babies inside. Suddenly Mark is attacked by one of the tentacle robots,
but he's saved just in time by Jarrod, whose eyes are red instead of blue like every other
light here. There are more enemies coming, so Mark follows Jarrod into another room as he explains
he wants to find his son. Jarrod cauterizes Mark's leg before taking him to see Elaine,
who is three months pregnant yet she's about to give birth. Elain explains that when she first
saw the light, she instantly became pregnant. On the other hand, her husband Jarrod became stronger
every time he looked at it, allowing him to become immune. When the alien put his brain in a robot,
Jarrod retained his sense of self. The alien usually takes the babies right from their bellies,
but Jarrod saved her from that tragic end. Mark helps Elaine give birth to a healthy baby girl,
but unfortunately Elaine dies in the process. Jarrod accepts to help Mark find Trent in exchange
for Mark getting the baby out of the ship safely. Neither of them notices the baby can make her
eyes glow red. Meanwhile Trent and Audrey wake up to find themselves hanging from some vines
on the ceiling. Trent manages to get the other flare from Audrey's pocket and cuts her vine,
then he grabs Audrey and throws her on the stairs. He jumps after her and together they start making
their way down, only to discover Sarge is hanging from a vine too. After Jarrod and Mark leave the
room, the captain finds Elaine's body and begins tracking the baby. Jarrod first takes Mark to the
armory, where he provides him with an alien weapon that connects directly to his arm's nerve cells.
Then Jarrod begins setting up bombs to blow up the ship. He also uses the main computer to find where
Trent is. At that moment, the captain shows up, so Jarrod opens a passage to send Trent to the vine
room while he stays behind to fight the captain. In the vine room, Mark finds Trent jumping on
Sarge's vine to rescue him. Making the vine swing, Trent frees Sarge while Mark puts down the baby
and rushes upstairs to offer his hand right before the vine breaks. Trent holds onto Mark's hand but
the robot's tentacles are stronger and sadly they drag Trent away to steal his brain and throw his
body into the pile. Another tentacle grabs Audrey, so Mark jumps on it and cuts it with the alien
blade Jarrod gave him. Audrey makes it safely to the floor and the robot falls on top of Mark,
but he uses the blade to finish it off. In the meantime, the captain overpowers Jarrod
and leaves him for dead. Jarrod is only pretending and reveals he still has a bomb in his hand. The
captain goes to the vine room and Mark tries to attack him, but the blade suddenly stops working,
giving the captain the chance to go after the baby. Sarge gets in his way to buy some time,
and he gets wounded while Audrey retrieves the baby. As the captain turns to go after her and
Mark, Jarrod finally activates the bombs and the ship explodes, crashing in rural Laos. The crash
is seen by siblings Sua and Kanya, who work with a cartel group. There are cops in the area trying to
stop the alien robots but also looking to arrest cartels, so Sua kills one off while officer Huana
is busy destroying the robot with a flamethrower. The siblings approach the ship and find one of the
eggs on the ground, which Kanya puts away in her bag. Mark, Audrey, and the baby have landed safely
thanks to the alien goo. Sarge is also alive but barely hanging in there because of his wound.
While the group leaves the ship by jumping into the river, the captain also wakes up alive and
begins working on making more robots with human brains. One of these is Trent, who sees his
memories for a second before the programming takes over. A moment later, Mark and the others reach
the shore, where they bump into the siblings. As they begin arguing over their intentions,
Sarge dies from his wounds. Sua feels bad and accepts to take them with them to their camp,
where Audrey changes the baby, who is growing at an alarming speed. While Mark is distracted
washing his hands, Kanya checks the object in his pocket and finds his badge; now the siblings think
he's here to spy. Sua attacks Mark and the two men engage in a fierce fight while Kanya tries to
keep Audrey away from the baby. Mark is keeping up well thanks to his training, but Audrey is
inexperienced and Kanya easily overpowers her. At that moment, Huana shows up with more cops,
so both fights are interrupted to make a plan. Mark promises to help if Sua can take them to
a doctor for the baby, and a truce is formed. Sua guides the group carefully through the minefields,
and when they stop to camp for the night, Mark tells them how there was only one real alien
on the ship. He wonders if the humans inside the robots can be freed like Jarrod did. Afterward,
Mark tells Audrey about Rose. The next morning, Mark is awakened by Huana. Sua immediately saves
him by shooting Huana non-lethally, but when he's about to shoot again to kill him, Audrey stops
him. Then she checks on the baby, who has become a young kid overnight. The group leaves with Huana
as their prisoner and they make it to an ancient temple, underneath which the cartels have set up
their hideout. Huana is locked in a cell and the kid is taken to doctor Harper, who confirms the
child is burning with fever. Harper proceeds to run some tests while Mark wonders if he can trust
this place. Sua shows him this was built during the war to defend themselves from the American
attacks, so if they can survive the USA they can also survive aliens. Moments later, Harper
announces the child isn't really human. Kanya runs away in panic and leaves her bag behind,
allowing Harper to find the egg. When Kanya tries to take the kid away for being the enemy,
the others stop her, and Mark tells her about the experiments he saw, meaning the child's also a
victim. Afterward Harper gives a full explanation: the kid's constant growth has depleted her entire
system, and she's about to shut down. She needs a transfusion, but Harper doesn't think any of
them are compatible. Mark shows him his arm and tells him about the weapon that was connected to
his body, so they decide to try with his blood. The next morning, the kid is healthy and well,
she's also grown even more. Using the egg Kanya found, Harper runs more tests and discovers
the blue light that brainwashes their brains is biologically compatible with human DNA. He thinks
the aliens planted humans here on Earth as a crop, and every couple of millennia they come back to
harvest. However they didn't take evolution into account. Using the egg and the kid's blood, Harper
develops a serum to be put inside the beam cannon, and the modified light will free all the robots
from the mind control. The group begins arming themselves for the incoming fight, and Audrey
and Kanya go outside to set up some traps. At that moment, the captain sends a giant robot to attack
Audrey. Kanya activates one of the traps but the bomb is just a scratch for alien technology,
so she gets its attention by shooting at it. Then Kanya runs into the minefield, and as the
alien follows her, it activates one of the mines. This explosion does more damage but it's still
not enough to destroy it. Kanya steps back and accidentally walks on a mine. Knowing there's no
way out, she uses her radio to say goodbye to her brother, and when the robot comes close enough,
she removes her foot. The mine explodes and brings them both down. The explosion has given away their
location, and the captain begins flying the ship toward the temple. Mark thinks they should leave,
but Sua explains his people will never stop defending the tunnels. Seeing as the chances
are low anyway, Mark asks for the serum so he can try to put it in the cannon while everyone
keeps the alien busy fighting. The cartels begin setting up traps all over the tunnels and Mark
leaves the child with the civilians in a room at the back. Mark manages to leave the hideout right
before the alien robots begin coming down the tunnels. The explosives do quite a lot of damage,
and the cartels finish the robots off with their firearms. Then Sua gets ready to start a fire by
the entrance, but an alien surprises them by entering the tunnel through a hole it makes in
the ceiling. The alien kills a bunch of people before it finds Sua, who fights it and guides
it back to the entrance so he can defeat it by setting it on fire. Since so many fighters died,
Sua frees Huana to ask him to fight too. Then all the survivors begin evacuating through a hidden
tunnel. Meanwhile Mark sneaks around the temple and enters the spaceship through a back door.
Remembering what Jarrod did, Mark opens a tunnel on the wall and takes it to reach the cannon room,
this is seen by one of the many guards. At that moment the cannon sends a light
out to try to brainwash the survivors that are coming out, but everyone remembers to
close their eyes. The child doesn't because she can defend herself by making her eyes glow red.
One of the cartels shoots a rocket at the light to destroy it, but before everyone can escape,
another giant robot appears piloted by the captain and begins destroying the place. Everyone begins
to fight the army of robots that arrives with the giant one, and when one of them is about to reach
Audrey and the kid, Harper gets in its way to save them, dying in the process. Inside the ship,
the guard finds Mark and attacks him. During the fight, Mark drops Rose's ring, and the sight of it
makes the guard hesitate. Mark realizes this is Trent, but since the boy can't completely
shake off the control yet, Mark has to push him away into the lower level to save himself. Then
he grabs an egg from the vines, injects the serum into it, and throws it into the beam, changing the
light color from blue to red. Trent immediately recovers his memories, but before the light can
reach the others, the captain uses his robot to break the beam cannon, causing Mark to jump off
the ship not to die along with it. Then Mark finds a broken robot and steals its blade so he can join
the fight. He, Sua, and Huana work together to keep the girls safe, and when the captain comes
closer with its giant robot, it's suddenly hit by the second one: it's Trent, who has stolen
its own giant from the ship. As both giants begin fighting, the captain quickly overpowers Trent.
Mark gives Sua the blade before he goes looking for the rocket launcher, which he shoots at the
captain's robot to give his son a chance. Sua and Huana keep on fighting the human-brained robots,
but unfortunately Huana is surrounded and dies. Audrey puts down the kid to help with the fight,
but as soon as she turns around, the kid leaves. Ignoring the battle around her, the child reaches
the fallen cannon and activates it again. The captain notices this and comes to kill her,
but Mark runs to protect her and Trent pushes the captain to the ground. Then Trent picks up the
cannon and shoots at the captain, finally killing it. This shot also makes a red light appear in the
sky, which frees all the human brains from the mind control. Father and son finally reunite,
and when Audrey picks the kid up, she decides to name her Rose. Some months later, Rose is
now a young woman and captain of a ship they've built with the pieces of the alien one. Her crew
is formed by humans but also by all the people trapped in the robot bodies, like Trent. Together
they're finally ready to fly to the aliens' home planet and stop them from coming back ever again.