In 2092, climate changes has destroyed most plants on the planet, making Earth nearly uninhabitable. A corporation known as the UTS builds a new orbiting home for humanity that mimics the natural processes on Earth, however only a few chosen ones are allowed to live there and even less than that can become citizens. Those remaining on Earth have to deal with the polluted air, high taxes, and extreme poverty.
Founder of UTS Sullivan is working on making Mars a new Earth by growing genetically modified plants. He tells a bunch of reporters about all his plans, announcing that the grand opening of a Mars colony will be soon. One of the reporters calls him out because projects so far have only helped the elite and left thousands of people back on Earth, not to mention all the debris flying faster than bullets in space.
Workers known as “space sweepers” have to risk their lives to clean that up, selling the debris later as their only income. Sullivan admits his plans aren’t perfect and agrees to have a talk with the reporter in private. On Earth, Tae-ho is desperate to find his daughter and tries to pay the authorities with the little rice he has left to let him see the latest body that arrived to the morgue.
They’re used to him doing this often and take him to the morgue, but once again it’s a false alarm. The next day a huge piece of debris crashes with a satellite near the solar battery charging area. A group of space sweepers hurries to get hold of it with their ships, but they’re suddenly interrupted by the arrival of a ship known as Victory.
Android Bubs stands on top of the ship and throws a harpoon with a rope that connects to the piece of debris. Then Victory takes off, causing the other sweepers to chase after them. Bubs starts rolling the rope to bring in the debris as Tiger handles the ship’s machinery so it can run fast and smoothly.
When the other ships get close and try to steal the loot, Captain Jang uses Victory’s arm to push them away without much trouble. Then pilot Tae-ho makes a risky move and flies Victory around the solar panels, flying through tight spaces to escape without a chance of being followed. This causes them to almost crash against the residential area, but Tae-ho moves the ship just in time and they only break an antenna.
Afterward they enter the Factory, which is a waste management satellite. Tae-ho sells all the materials they’ve gathered but the pay is poor, and of top of that they must pay for the antenna and the corresponding taxes. In the end, the team is left in debt.
Tae-ho reacts badly and the clerk threatens him with a knife to calm him down. On TV, the news show a missing sign for an android called Dorothy, who was stolen from UTS two days ago by extremists known as Black Foxes. The girl looks innocent but she’s actually a weapon, so if civilians see her, they should call security instead of approaching her.
However Tae-ho doesn’t pay much attention and leaves. That evening, the tension is high among the Victory crew because of their debt situation. An argument ensues and it soon becomes an actual fight that leaves the humans unconscious.
Bubs puts away her money in a box, revealing she’s the only one that has been keeping proper savings. Her dream is to get a better body with synthetic skin. Later the crew goes out to work on the debris they picked up, which turns out to be a broken ship in a rather good condition considering it came from an area full of nanobots that eat metal up.
Suddenly some lights activate inside the ship, so they open up the cargo box and watch a bunch of air bags float out. Hidden among them, they’re shocked to see Dorothy. They take her into Victory and Tae-ho can’t help thinking about his own daughter when he looks at her.
At that moment the news show the missing ad again and the crew gets scared when they hear she’s a weapon, quickly running for cover when she opens her mouth. However she’s just sneezing. Then the crew runs to hide in their rooms and decide how to proceed.
Tae-ho comes out again to try to tie her up, but as soon as she moves he gets scared and hides behind some metal. At that moment he notices she has a bag, so he grabs it and takes it with him to his room to examine its contents. There’s a phone with lots of missed calls for someone named Doctor Kang and some paperwork from UTS with the same name.
The crew decides to fly toward one of the residential district for non-citizens. They leave the ship but Dorothy stays behind and when she’s alone, she reveals a power that causes a dead plant to bloom. Meanwhile the crew goes to a bar and discusses what to do.
Tiger tried calling the police and was left on waiting, but Tae-ho thinks they can make good money by selling Dorothy to the Black Foxes. An argument ensues and once they all reach an agreement, Tae-ho takes out a machine that distorts his voice and isn’t traceable. He calls Doctor Kang and shows him a video of Dorothy, asking for two million in exchange for the girl.
Kang immediately agrees to pay and they decide on a meeting spot. While the crew dresses up for the exchange, an alert rings in the computer, revealing the police are coming. They immediately take off the disguises and hide the girl, acting normal right before an officer comes aboard.
The cop explains his station got a call from this ship and notices Tiger gesturing at someone behind a door. With a taser in hand, he enters the room to search for anything suspicious, but Dorothy sneaks around and always stays hidden. Tae-ho takes some of Bubs’ savings and puts in the cop’s hand before the guy pushes him away.
However the cash is still in his fingers and Bubs recorded everything, so Jang threatens to report him until he leaves. Afterward Tae-ho and Tiger put on the costumes again and go to a club in the commercial district for the exchange. While Tiger keeps Dorothy safe in a bag, Tae-ho moves to meet with Kang, who surprises him from behind and checks for weapons before telling him to move.
In a balcony nearby, some guards get ready to shoot. The duo meets with Tiger and Kang hands him a suitcase with the money, but when they open the bag they discover Dorothy is gone. The girl is wandering among the dancing crowd, who suddenly freezes when they notice a child.
At that moment everyone’s devices start showing Dorothy’s missing ad and they step back in fear. The guards open fire and Tae-ho drags her out of the way just in time, but the shots destroy the DJ booth and chaos ensues as everyone runs away in panic. Kang keeps trying to reach Dorothy but the running crowd pushes him along.
As Tae-ho and Tiger keep looking for Kang, a guard notices them and fires right at them, however Dorothy’s power creates a shield that dissolves all the bullets. The guards still keep on shooting until there’s not a single presence left in the room, thinking they’ve killed their objectives. However the guys managed to sneak away with Dorothy and they’re leaving in Victory now.
Since the ship has damage, they must stay in the Factory. After scolding them for failing, Jang destroys Dorothy’s phone because she thinks the guards used it to track them. She saved Kang’s number so they can contact him with their own communicator.
In the meantime Sullivan is chatting with his scientist team about the nanobots on Mars that are trying to build plants and even an ocean. Someone brought him Dorothy’s goggles from the club and he keeps staring at them as he scolds his team, saying they must find evidence that there’s no hope on Earth. His veins gain a dark color as he wiggles in pain.
Sometime later Dorothy asks Tae-ho for scissors and uses them to cut off the tomatoes that have grown on the plant. Tae-ho is impressed and takes Dorothy with him to sell them to other sweepers, making some money but also bonding in the process. Afterward it’s Bubs’ turn to watch over Dorothy and they share make-up.
While they chat, Bubs’ scan discovers a secret about Dorothy, but the girl changes the subject to ask about Tae-ho. Bubs explains Tae-ho was a child soldier, and for most of his life he knew nothing but violence. One day during a mission, his team killed a mother and he found a baby in the arms of the dead body.
Instead of sending her to Earth like the rules said, he adopted her as his daughter. Soon he discovered that the explosion from the mission had left her deaf and he blamed himself, so from then on he wasn’t capable of hurting people anymore. This caused UTS to fire him and they ended up in a poor neighborhood.
One evening while Tae-ho was trying to make some money, his daughter wandered away. Suddenly some space debris crashed in the neighborhood, killing thousands of people and sending the others running in panic. In the chaos, Tae-ho couldn’t find his daughter and watched in horror how part of the town flew away into space.
Later the authorities explained they had about three years to find the body, after that there would be zero chance of recovery because the debris would be too far away. A search company could be hired to find her quickly, but he couldn’t afford them. To this day Tae-ho is still looking for her, that’s why he joined a sweeper crew.
Bubs’ story is interrupted when some court agents find her with Dorothy. At that moment the ship’s phone start ringing and Tae-ho tries rushing to it, but the agents stop him. A desperate Tae-ho just pushes them away and manages to get the call, during which he agrees to a new meeting with Kang.
Unfortunately the court agents seize Victory, announcing it’s now property of the bank because of the crew’s debt. In private, Tiger admits he doesn’t want to sell Dorothy anymore because he fears what they may do to her, but Tae-ho needs the money to find his daughter and the crew needs to get the ship back. When Dorothy goes to the bathroom, a man follows her inside.
Suddenly the crew hears her scream and they realize she’s been kidnapped. The crew immediately starts looking for her and Tiger remembers the tunnels, so he jumps in there to find a man taking Dorothy away. A chase ensues and Tiger loses sight of them, but Tae-ho arrives just in time to take Dorothy from the kidnapper by surprise.
Then the guy takes out a blade, only for Tae-ho to quickly bring him down with his soldier training. Unfortunately the man isn’t alone and more masked criminals come out at the same time Tiger returns, angrily beating them all up in just a matter of minutes. Jang also comes and unmasks the leader, discovering the clerk that usually buys their debris.
In the meantime, Sullivan is having a meeting with the reporter that called him out. Sullivan explains he doesn’t choose the citizens according to their economic status, his system runs DNA tests to choose the people with the best genes. The reporter points out that UTS is draining Earth’s economy and creating too much space waste, effectively accelerating Earth’s death.
Getting creepy, Sullivan starts describing how he saw everyone in his village die when he was young and he lost his family, so since then he promised he would make humanity better. At the same time his guards bring an unconscious Black Fox and drop him on the floor. Sullivan tells the reporter he’ll make him a citizen if he shoots the fox, and the reporter does it after some hesitation.
However Sullivan sees this a proof the guy is trash and kills him while his skin changes color. Back to the crew, they confront the kidnappers while Dorothy rushes to the bathroom. Jang points out robots don’t poop and concludes Dorothy is human, which Bubs confirms.
Then she uses a special light to reveal the kidnappers’ tattoos, proving them to be Black Foxes. The group explains the foxes aren’t terrorists, they’re actually an environmental organization. Dorothy was born with an illness that destroys her nerves, so her father Kang injected nanobots into her body.
These repaired her nerves but also gave her special powers to make plants grow; this meant she could heal Earth and Sullivan’s Mars’ project wouldn’t be needed. When Sullivan heard about Dorothy, he sent his guards to kill her. The labs and scientists that worked with her were destroyed, but Dorothy couldn’t be killed because the only way to kill a nanobot is to use a hydrogen bomb.
Such a bomb can be found inside the Factory’s anti-gravity system, so the soldiers want to put her there and blow it up, then the Factory would crash on Earth and cause enough natural and nuclear disasters to finally put an end to it. In short, Sullivan wants to cleanse humanity. Suddenly they hear some gunshots and discover the soldiers have arrived at the Factory and are looking for them by hitting any person they see in the way.
The Foxes escape through the back door while Jang and Tiger walk normally through the corridors, pretending they’re random workers. Tae-ho takes Dorothy and they escape through the vents, but Dorothy sneezes and a soldier sees them. They start moving faster as the soldier opens fire and Jang creates a distraction by activating Victory.
Tae-ho and Dorothy manage to make it to a bridge and run as they dodge the fire from the guards, jumping at the last second to grab onto the ship before it leaves. When a soldier also jumps and lands on top of Tae-ho, it pulls at Dorothy until they’re both falling. The soldier makes a perfect landing and gets ready to catch the girl, only for Tiger to swing by and catch her first.
Once everyone is aboard, Tae-ho flies out as fast as possible. There are missiles following them and one explodes too close to the ship, sending it flying into the debris field. Soon Victory starts failing and the crew can’t keep up with all the necessary repairs, which allows a nanobot infestation to get into the ship.
As the nanobots cover the entire Victory, Dorothy activates her powers and sends them all away in seconds. Then she passes out and Tiger notices her heart has stopped, so he immediately starts CPR. To his surprise, Dorothy farts and wakes up as if nothing happened.
Soon Victory leaves the debris field and picks up the news, which announce the crew members are now wanted criminals. They’ve been classified as members of the Black Foxes and even blamed for the attack at the club and the Factory. At the same time, Sullivan is going through a medical treatment while looking at the crew’s files.
Jang used to be an engineer for the UTS Genius Program and invented some important devices, however she deserted at nineteen for form an anti-UTS organization. She tried to assassinate Sullivan but failed, and her whole group died during the attempt. Tiger used to be a cartel leader on Earth who fled the planet to avoid capture since he was sentenced to death.
If he’s ever caught, he’ll immediately be executed. Tae-ho was was the inaugural commander of the Space Guard and the first soldier who Sullivan carried into the company in his own arms. Moments later, the Victory crew gets a message from the foxes and they meet inside an old colony.
Soon they come aboard and Dorothy runs to reunite with Kang while Jang notices something strange: this place is covered with EMP explosives, which then activate and shut down all the ship’s systems plus Bubs. At that moment the soldiers enter Victory and start shooting down the foxes before kidnapping Dorothy. Jang’s crew tries to help her, but the soldiers quickly knock them down.
The trio only gets arrested, but all the foxes are killed including Kang. Sullivan arrives and puts a hand in Jang’s mouth to extract a micro-chemical bomb that she almost used for self-destruction. He doesn’t kill anyone because of their shared history and instead monologues about his plan.
Then he drops a bunch of money as payment for Dorothy, mocking Tae-ho for grabbing it to find his daughter. Afterward Sullivan tells his people to put Dorothy in the Factory and crash it on Earth. Then he appears as a hologram for all the UTS citizens and announces Mars is ready to be lived in.
Back in Victory, Tae-ho is collecting his part of the money, but the others consider it dirty and don’t want it. In fact they want to rescue Dorothy and ignore Tae-ho when he says they’ll die trying. While Dorothy is tied to the hydrogen bomb, Tae-ho goes to the search company and pays them to find his daughter.
While waiting he looks at her old things and finds some loving words she wrote for him even though during those days he was only a drunkard that ignored her. Realizing he’s doing the same now, Tae-ho runs back to Victory and agrees to help rescue Dorothy. As Tae-ho flies as fast as he can, Jang takes our her old gun from her rebel days and stands outside the ship to open fire at the incoming soldiers.
She can’t keep up with everything, so Bubs comes out and starts swinging among the enemy ships, destroying them with her harpoon. Unfortunately the harpoon breaks and Bubs has to go back. Tae-ho asks Tiger to push the machinery to its limits and starts flying toward Earth, only to pull Victory back at the last second.
The missiles following them aren’t fast enough and burn down when crossing the atmosphere. There are still a few ships following them, but Victory goes fast and enters the Factory just in time. The crew rushes inside the gravity chamber and rescues Dorothy.
Jang checks on the bomb’s programming and discovers the detonator is inside it, so it’ll go off if she tries to hack it. They need to take Dorothy over five thousand kilometers away so the shockwaves won’t destroy her nanobots. Their discussion is interrupted by the arrival of a soldier, who quickly knocks Tae-ho and Jang out.
Tiger tells Dorothy to run back to the ship while Bubs tries fighting the soldier, but she is easily defeated too. Then Tiger tackles the soldier into a corridor and locks the door behind him. Tiger tries his best to fight, but the soldier is too strong and easily beats him up.
A desperate Tiger chooses to open the hatch, causing both of them to be sucked out by the pressure change. With his ax, Tiger defeats the soldier and climbs back into the chamber. The crew gets ready to leave only to hear there are attack drones coming.
Jang opens communications with the other sweepers and explains Sullivan’s plan, asking for help. Jang flies Victory out of the Factory as fast as possible as Jang shoots as many drones as she can. When they make it outside, they discover all the Factory workers and other sweepers waiting in their ships.
By working together, the sweepers start bringing down dozens of drones at the same time with impressive aim, allowing Jang’s crew to safely fly away to save Dorothy. Meanwhile the recording of Sullivan’s monologue made by Victory is sent to the news and now all humanity knows the truth. A furious Sullivan leaves in his own ship and finds Victory, opening fire to stop them.
Jang fires back as Tae-ho flies as fast as possible, but all the shaking causes some metal to fall and trap Jang under it. Suddenly Sullivan uses a mechanical arm to hit Victory, and Jang ends up floating away from the ship. Next Sullivan climbs on top of Victory and Bubs tries to stop him, only to get cut in two.
A wounded Jang manages to hold onto the ship and reaches the booster system, activating it just in time to send Victory into a flying speed that throws Sullivan off. Unfortunately the booster doesn’t last long and Sullivan reaches Victory again, breaking it open with the mechanical arms. To his shock, he finds the bomb inside.
It turns out the crew took the bomb with them when they left the Factory and dropped Dorothy with the other sweepers before they flied away. This way they acted as bait for Sullivan and saved everyone at the same time, even if it costs their lives. The other sweepers watch with tears as the bomb goes off, killing Sullivan and destroying Victory.
At that moment Dorothy activates her powers and controls the nanobots, which safely bring the biggest piece of Victory out of the explosion with the crew still alive inside. Sometime later UTS apologizes for the cover-up and promises to start working on restoring Earth. The sweepers are paid very well for their heroism, so their debt is gone and Bubs finally has the body she wanted.
Tae-ho takes Dorothy to the search company and she connects to the nanobots in the debris area, which allow her to search for his daughter’s DNA. A projection of her body appears and Tae-ho meets her in the astral plane to say goodbye. The crew adopts Dorothy and lives like a happy family as Earth becomes green again.