During a NASA special event, the CEO of Genesis Nathaniel presents his plans to colonize Mars, saying they only need to add water. He also introduces the team of six geniuses that will be leaving soon to prove that it’s possible. The lead astronaut is Sarah, who answers a few questions from the crowd and explains four years on Mars aren’t a sacrifice but an opportunity.
Afterward the crowd rushes outside to watch the astronauts board the rocket and leave the planet in a very impressive launch. The rocket parts split and the pod with the astronauts carefully moves to dock with the station that will take them to Mars. Two months later Sarah is throwing up again and her colleagues worry.
Soon big news reach Nathaniel on Earth: Sarah is pregnant. He refuses to make the team come back and announces the baby will be raised during the mission, but they must keep it hidden from the public. When they finally make it to Mars, Sarah immediately gives birth to a healthy baby boy.
Sadly she only gets to hold him for a few seconds before her heart rate starts dropping. The team tries their best to help her, but it’s too late: Sarah has died. All of this is broadcasted to Nathaniel, who rushes back to the company to discuss the situation.
Mars’ gravity will alter the child’s organs, meaning the heart won’t be strong enough to work on Earth’s gravity and his bones will be oversized. There’s no way he could survive coming to Earth. Nathaniel wants to go public with this and take full responsibility, perhaps even go to Mars too.
However Director Tom refuses and reminds Nathaniel that he’s sick, so he would’t survive the trip. In the end they agree to let the child grow up in Mars and keep him a secret. Once the meeting is over, Nathaniel gets into a spacecraft and tries to leave the planet.
The take-off goes well, but as the spaceship leaves the atmosphere, things get complicated and Nathaniel loses control. Suddenly all movement stops and it’s revealed this is a simulation that Nathaniel has failed, judging by the messages saying “all perish” on the screen. Sixteen years later, the Mars colony is actually thriving and the boy has grown into a teenager named Gardner.
When he asks his robot for a map of the ventilation system and the robot refuses, Gardner rips its head off and uses it to access the system. He watches videos of the mission launch and knows who his mother was. His snooping is interrupted by a message from Kendra, the astronaut who raised him.
She reminds him it’s his shift at the greenhouse and calls him indispensable, but Gardner can’t believe that because nobody knows he exists. Moments later, Gardner finally obtains the map of the vent system and sneaks inside it to reach a room he usually isn’t allowed into. Here he opens a locker and finds a box with Sarah’s belongings that he takes to his room.
There's a ring and a flash drive disguised as a branch, which Gardner connects to his computer. The files contain pictures and videos of Sarah and a man during a beach vacation, causing Gardner to assume that’s his dad. After printing a screenshot of the couple, Gardner receives a message from Tulsa, his online buddy from Earth.
Tulsa lives in Colorado and is stuck in the foster-care system, which she hates. She doesn’t know Gardner’s secret because he hides his IP and pretends he’s living on Park Avenue but can’t leave the house because he’s sick. They talk every day and they’re very close friends regardless of the distance.
Afterward Gardner watches a movie with Kendra about an angel that is willing to lose his powers to be with a human woman, which Gardner finds very inspiring. On Earth, Tulsa practices some music in secret but stops when she sees some guys at the window laughing at her. Annoyed, she leaves the school on her bike, ignoring the guys trying to come after her and throwing nasty comments.
After a ride through the mountains, Tulsa makes it home, only to find her foster father unconscious because he drank too much. She wakes him up and drags him to his old biplane, asking him to pilot it. Her dad says she should do it instead, but Tulsa doesn’t dare.
Back to Gardner, he makes sure nobody is around and makes a jump to press a sensor that hacks the lock and open the door. This jump leaves him in pain and hardly breathing. Then he suits up and leaves the base on a car to visit Sarah’s grave.
This only causes him to be more frustrated about his situation so he starts driving like crazy to blow off some steam, however this causes the car to lose control and flip. Gardner’s suit breaks and he starts losing oxygen, but luckily Kendra has been following him and arrives just in time to save him. When they return to the base, Kendra scolds Gardner for not being responsible and wonders how he got past the electronic lock.
Gardner reveals he used the magnetic implant that monitors his organ growth. Kendra then tells him that Sarah’s grave is just a memorial and her ashes were spread across the Pacific Ocean. Moments later, Kendra makes a call to talk to Nathaniel and Tom.
She tells them how smart Gardner is and how he’s hungry for socialization. When Nathaniel points out Gardner wouldn’t survive the trip, Tom cuts in and reminds him NASA is angry with him because he disappeared after the baby’s birth. NASA was never happy with the child situation and wants him to come to Earth.
There are few procedures that could help Gardner survive the trip, but Nathaniel still refuses to sign the authorization. After hanging up, Kendra decides to act behind Nathaniel’s back and tells Gardner he can start going through the necessary steps to go to Earth. Gardner immediately messages Tulsa, telling her that they’ve found a cure for his illness and he’ll visit her soon.
Next Gardner undergoes a very risky procedure to increase his bone density, followed by tons of physical therapy to get him used to Earth’s gravity. When he isn’t training, Gardner takes all the money from the crews’ wallets in storage. He also watches romantic movies to learn more about courtship.
Once Gardner is finally ready, he and Kendra leave in a shuttle that is taking a few astronauts home. While they chat, Gardner asks about his father, but Kendra swears nobody in the crew knows his identity or any details about him. On Earth, Nathaniel checks the Mars security cameras and the crew files, discovering that Gardner is gone.
He runs to the NASA offices and talks to Tom, who had been working with Kendra behind the scenes. Nathaniel demands to see the boy when he arrives, but Tom says it’s impossible. When the shuttle gets close to the planet, Gardner is overwhelmed by its beauty.
As soon as they land, a NASA team gives him shades to protect his eyes from the sun and a mask to protect his lungs, but Gardner is very distracted by the sea because he never saw so much water before. Afterward they take him to the lab to run some tests and make sure he’s fine. Later that day Nathaniel is finally allowed to visit Gardner, who continues to be impressed by all the colors and his own new weight.
They start exchanging questions about life on Earth versus life on Mars, but they’re interrupted by Kendra. She and Nathaniel join another meeting with Tom and they agree to keep Gardner in quarantine a bit longer until they make sure everything is well. When Kendra gives Gardner the news, he immediately complains because he’s tired of being locked-up.
As soon as he’s left alone, he sneaks out of his room and opens a bunch of gas tanks to fake an emergency. By the time the alarm starts wailing, he’s in the locker room stealing a suit to hide among a group of students. While security tracks him on the cameras, Gardner enters another building and steals some clothes from a worker.
Using his implant again, Gardner opens the back door and gets access to the loading bay, where he takes the chance to hide inside a truck. By the time Nathaniel and the guards arrive, the truck is already gone. A few hours later when the truck finally makes another stop, Gardner gets out and almost gets run over by another vehicle in the street.
He dodges just in time and keeps going until he finds a hobo with a fire. Gardner is amazed by the flames and even exchanges his shades for the man’s, he also gets directions for the bus station. While waiting for the bus it starts to rain, and Gardner enjoys the feeling while everyone else runs for cover.
Meanwhile Kendra is helping Nathaniel search for Gardner and she looks at his computer files, learning about his friend Tulsa. Eventually Gardner makes it to Colorado and goes to Tulsa’s school to finally meet her in person. When she realizes who he is, she slaps him for ghosting her for months.
Gardner apologizes and explains his trip required a very specific kind of transportation method that didn’t allow him to send texts. Tulsa calms down and tells him to wait while she finishes her classes. However he gets bored and follows her into the classroom, where he impresses the teacher and the other students with his science knowledge.
Suddenly Gardner notices a handle and pulls it, not knowing it’s the emergency wash station. Some water falls on him and he finds it amusing like everyone else. After class, Gardner tells Tulsa he’s from Mars but she doesn’t believe him.
He shows her the picture of his mom with the man and explains he wants to find him. Then Tulsa takes him to her house, only to find Nathaniel and Kendra already there. Gardner refuses to go with them and starts running away while Tulsa’s dog keeps them at bay with some ferocious barking.
Kendra manages to follow him anyway, but before she can catch him, Tulsa shows up in her foster father’s biplane. As Nathaniel joins the chase in a van, Gardner runs fast enough to jump on the biplane and Tulsa finally takes off. As they fly away, Gardner is amazed by the feeling of the wind and the great views.
Eventually the biplane starts running out of gas so they must do an emergency landing. Tulsa chooses the freeway and starts going down, only to see a truck coming toward them. Thankfully Tulsa reacts fast and manages to fly above it.
Then she finally lands, causing a bunch of cars to drive off-road. The biplane doesn’t have brakes and keeps going, getting too close to a building. The teens quickly jump off the plane, saving themselves right before it crashes against the building and explodes.
Meanwhile Nathaniel and Kendra have been following them on a helicopter. When Nathaniel makes a sudden move, Kendra accidentally drops the tablet with the GPS and footage. By the time she picks it up, she only sees the explosion and assumes the teens are dead.
After Tulsa and Gardner run away, a bunch of firefighters, cops, and agents from NASA appear on the area. Tom confirms there are no bodies, meaning the teens are alive. Nathaniel freaks out and blames everything on Kendra, who has a breakdown and reminds him she’s been leading the Mars mission all these years when that was originally his job.
Moments later Gardner and Tulsa make it to town and Tulsa uses a phone to steal a car from a dealership while the owner is with a client. The duo travels through the countryside and Tulsa asks Gardner more questions about his life, but she still doesn’t believe him when he says he’s from Mars and he’s being chased by NASA. Furious, she stops the car and starts yelling at him, explaining she’s tired of everyone in her life lying.
Gardner shows sympathy for her situation and behaves like the gentleman from the movie to get her back in the car. At that moment Gardner gets scared when he sees something big moving on the road, so Tulsa has to explain it’s just a guy riding a horse. A few hours later, the duo stops at a diner and wait for a mother to rush with her child to the bathroom.
Then Tulsa uses the tablet the mother left on the table, pointing out it won’t be traced like her phone. She finds Sarah’s story on the internet, but her death has been covered up with a fake suit failure story. Then Gardner brings out the ring and Tulsa notices it’s half of a bigger one.
It also has some engraved words on it, so she searches them and learns that they’re written in the language spoken by a native tribe in Arizona. It means “reunion of halves, love, eternity” and it was signed by a shaman, causing them to conclude this is a wedding ring. At that moment the guy behind them takes a selfie with them.
To make matters worse, the police have arrived and the mother is coming out of the bathroom, so the duo has to escape. Meanwhile Nathaniel and Kendra are informed by the police that they found a pair of runaway teenagers, but they turn out to be the wrong people. Nathaniel starts freaking out and admits he’s made many mistakes, like giving up.
Then Kendra gets a call from the lab saying that the tests results aren’t good and Gardner won’t survive much longer if he stays on Earth. Back to Tulsa and Gardner, they’ve stolen another car and they’re enjoying their trip to Arizona. Gardner keeps getting amazed by things like balloons, new food, and even a harmonica.
When they find a mall, they get new clothes and some supplies. Tulsa finds a piano and plays a song she wrote, which Gardner finds beautiful. Soon the mall’s security footage reaches the hands of Nathaniel.
Once they’re back on the road, Tulsa teaches Gardner how to drive and he uses the chance to repeatedly tell her she’s beautiful. It makes her feel a bit awkward, so he squeezes her knee to calm her down. That night they stop to make camp.
Tulsa plays some music on the car radio and dances with Gardner until they kiss. Then they share the sleeping bag and have their first time together after Gardner tells Tulsa she makes him feel human. The next day they find a woman in the area and ask her about the shaman.
Luckily she knows him and takes the teens to see him. The shaman checks his records and finds the check Sarah used to pay for the ceremony, which has her address but no mention of the man. Since the shaman has a computer, Tulsa uses it to search the address and look for views that match the picture.
At that moment Gardner’s nose starts bleeding, so he turns around and cleans it off before she can see it. Tulsa’s search is successful and finds the place from the picture. On their way out, the other woman tosses flower petals at them so they share a kiss.
After many hours of driving, the duo decides to spend the night in Las Vegas. Tulsa tries to show Gardner all the buildings that imitate famous places from around the world, but Gardner finds it too overwhelming and fake. He starts feeling dizzy and his nose bleeds again until he passes out.
Gardner’s immediately taken to the hospital, where the doctors run tests and notice his strange bones, not to mention his enlarged heart. Tulsa also sees this and realizes he wasn’t lying. When Gardner finally wakes up, he wants to leave immediately.
At first Tulsa tries to stop him, but Gardner explains the hospital can’t save him anyway so at least he wants to finish his mission. The duo sneaks out of the hospital and steals another car to escape right before social services arrives. Sometime later the duo finally makes it to the place from Sarah’s picture.
Gardner is very weak and Tulsa has to help him walk. They find the guy and show him the picture, explaining that the official story is a lie and Sarah died during childbirth. When Gardner says the man is his father, the guy freaks out and tries calling the police.
Tulsa stops him and yells at him until the man explains Sarah was his sister. Devastated by the news, Gardner starts walking toward the sea. When Tulsa tries to stop him, Gardner explains his mother’s ashes are here and that since he didn’t choose where he was born, he wants to choose where he’ll end.
After the couple shares a kiss, Gardner falls into the water, only for Nathaniel and Kendra to show up to the rescue. Together with Tulsa they drag him out and lay him down on the sand. Gardner starts asking questions about his mother and the way Nathaniel answers them finally makes him realize he’s his father, which Nathaniel confirms.
Afterward an ambulance rushes Gardner back to NASA and once he’s stable enough, they put him in a shuttle to take him back to Mars and Tulsa comes along. He doesn’t have much time left and the pilot refuses to go faster because of regulations, so Nathaniel takes over the controls. The shuttle begins shaking a lot under his command, but he’s desperate to save his son and this time he doesn’t make any mistakes.
The shuttle safely makes it to the stratosphere and Tulsa wakes up Gardner, who immediately starts feeling better. The teens hold hands and float together while confessing their love for each other. When the shuttle stops at the station, Gardner has to say goodbye to Kendra and Tulsa, who can’t come along.
Tulsa watches in tears how Gardner returns to Mars for the sake of his health. Sometime later, Gardner is healthier and wearing his mother’s ring. He and Tulsa are still chatting online every day.
One afternoon Kendra visits Tulsa and explains nowadays she trains astronauts at NASA and that she has a big empty house that makes her feel lonely, so she volunteers to adopt Tulsa. The girl is happy to accept and soon she joins the training program too. Meanwhile on Mars, Gardner gets to know his father better.
