In a starcraft funded by the Hyperion company, three astronauts are leaving on
a two-year mission to Mars. The crew includes mission commander Marina, biologist David,
and medical researcher Zoe. The take-off is a bit bumpy but Marina is an excellent pilot and quickly
takes control of the situation, getting them to leave Earth safely. She begins a careful spin to
create artificial gravity and unspools their solar panels, and this spin makes David feel a bit sick
while Zoe enjoys it like a roller coaster ride. This is Marina’s last mission before retirement,
so it is extra important for her to do it well. When they safely attach the ship to the station,
David takes a moment to recover while Zoe explores around, admiring the beautiful view
of Earth through a window. They hang up some memorabilia in their new bedrooms and find a
wall with the signatures of previous astronauts, so they add their own. They also put down all
the equipment they’ll need for their experiments. Once everyone has settled in and has had a snack,
they connect to the base for an interview, during which Zoe talks about how she applied to Hyperion
as a joke but once accepted, she saw it as an amazing opportunity. David explains it will be
difficult to leave his wife for two years, but his research into making life possible on Mars
is essential to one day making a second home for humanity. Later while checking the systems,
Marina notices blood on the ground, and she looks up to discover it is dripping from a compartment
above. With a power tool, she proceeds to open the compartment and suddenly an unconscious man
falls out, crushing her arm in the process. As air begins escaping from the broken panel,
David and Zoe come to take the stranger to the infirmary while Marina tries to repair
the damage on the compartment to no avail. After sealing the door to avoid losing more oxygen,
Marina finds the man’s ID and learns he’s Michael, a member of launch support. Marina calls Hyperion,
but they're unsure how Michael ended up on the ship. At the infirmary, Zoe cuts the man’s
shirt and finds a serious bleeding wound that she immediately patches up with stitches. Afterward,
Zoe 3D-prints a cast for Marina so she can keep her arm safe while it recovers. Marine notes that
with the ship's damage, carbon dioxide is higher than it should be, and David immediately uses
their extra tanks to fix it. When Michael finally wakes up, he is shocked to find out he's in space
and starts to freak out. Zoe calms him down with soothing words, and the rest of the crew joins
them for some questions. Michael says he is a launch engineer, that he remembers arming the
second stage firing pins, and that he thought he was clipped in, but he has no memories after that.
When he hears they took off twelve hours ago, he panics again as he explains he needs to get back
to his sister because she's alone. Marina explains they're moving too fast and don't have enough fuel
to turn around, but she assures him they shall check with Hyperion for a solution. Later the
crew shares their food with Michael, and Marina tells him that Hyperion checked on his sister.
She's doing okay, and they are hiring a full-time guardian, covering every expense. Michael
apologizes for freaking out and says that he won't just sit around, he is a quick learner and will
do any chore they can give him to help around the ship. The crew officially welcomes him into
the team and Zoe gives him a tour of the ship, including showing him the wonderful view of Earth.
He also tries to wash the blood off his shirt to no avail. Since there are only three beds, Michael
has to sleep on the stretcher, and it’s quite a restless night for him. The next day, Michael is
given his first task, which is helping David with data entry. David checks on his plants and tells
Michael what to write down while they listen to some weird jazz music. Michael teases him for it,
and David explains that the unpredictability of jazz together with its pure and messy expression
allows it to find a balance. Meanwhile Zoe puts on an astronaut suit and enters the broken corridor
to try to repair the compartment with Marina’s guidance. Zoe takes a picture of the machine and
sends it to Marina, who is devastated to see the results. There has been a short that fried the
machinery needed to keep CO2 at safe levels and keep the crew breathing, so this may get
dangerous soon. Afterward Marina nervously calls mission control to report that they have a damaged
life support assembly, and they promise to look into it. Next Marina asks to speak with David in
private. She asks him if he can use his equipment to produce more oxygen here instead of saving the
plants for Mars, confessing what happened to the compartment. David says that there might be a way
for him to pull it off, and before he leaves to work on it Marina tells him to keep this between
them. David immediately goes to his lab and using some empty bottles, he begins expanding his algae
production. In the meantime, Michael puts on a suit and joins Zoe in the damaged room. Together
they remove the compartment, but once they are done, they notice Michael's stitches reopened,
so Zoe quickly takes him to the infirmary. While she tends to his wound, he thanks her for not just
for doing her job as a doctor but also for making him feel welcome. Zoe asks him to remove his shirt
so she can have better access to his wound, and this reveals a big burn scar on his chest. Later
David reports back to Marina, explaining he used up half his algae and got about half the
oxygen output they need. Marina tells him to use the other half too, and this greatly upsets him:
using it all would leave him unequipped to do his research once they reach Mars, ruining years
of work. David doesn’t want to throw all that away when they could still fix the compartment,
but Marina finally confesses that it is damaged beyond repair. Now David has no choice but to
use all his plants. He destroys a few that had managed to grow well and sets up more bottles
to expand the algae cultivation. Sometime later, Michael sends his sister a video message about
how things are going for him. He had thought he would be a burden, but he has really found his
place on the crew, helping out where he can and truly befriending them. They’ve even allowed him
to sign the wall with all the other astronauts’ names. Going to space may have been an accident,
but it has become a great opportunity. Meanwhile David checks on the second batch of algae and is
devastated to discover that it failed. Marina has to hold back tears when she reports this to
Hyperion and walks through their limited options. Afterward, she breaks the news to Zoe, explaining
that even with David's work on the algae there is only enough oxygen on board for three people to
survive. When she implies that they may have to get rid of Michael, an argument ensues,
and Zoe is disgusted by how easily they would get rid of a human life before truly wasting all their
options. Zoe points out they had a giant tank of liquid oxygen used for the launch that could still
have some oxygen left, but Marina says they have no way of knowing for sure and it would be way
too risky to climb the tether to check. When Zoe wants to consider other options, Marina tells her
Hyperion already checked every possibility, but Zoe still refuses to accept it. Since they can
last another twenty days before it is too late, Zoe says they should wait and take as long as
possible to figure out a solution, so Marina ignores David’s disagreement and gives Zoe ten
days. They also agree to keep things from Michael for now. After their meeting is over, Marina talks
to Hyperion again and has to defend her decision to wait, explaining that the crew should look for
a solution even if it's futile otherwise they'd be too racked with guilt to cope. Three days later,
Zoe is checking on Michael’s wound and he notices her looking at his scar, so he shares the story.
He was nine when his apartment caught on fire, which orphaned him and his sister. He's taken
care of her ever since that night and they only have each other. Later, Zoe sobs quietly in her
room. Tired of waiting, David makes a decision to break the rule and he approaches Michael,
telling him they have tried everything they could but it is impossible to get more oxygen. Every
day Michael is with them presents a danger to the crew and the entire mission. David thinks that if
there was another way, Hyperion would already know by now, so he hands Michael a lethal injection,
promising it will be painless and apologizing before leaving. Michael sobs as he looks at the
bracelet his sister made him, then he inspects the deadly needle. Deciding he must do the
right thing, he sends another video message to his sister apologizing that he can't be with
her every step of the way and reminding her how tough she is. Even during this difficult message,
Michael speaks of the crew fondly. Moments later, Zoe finds Michael staring listlessly into space
with the needle next to him because he hasn’t been brave enough to do it yet. Zoe tells him
he doesn't have to, and while Michael is thankful that she keeps fighting for him, he thinks it's
hopeless. However Zoe disagrees and shares a story of her own: twelve years ago, she tried to save a
drowning man at the beach. She spent five minutes just trying to keep his head above water, nearly
drowning herself, then they happened to get saved by a passerby in a boat. She hadn’t known someone
was coming, she just had hope. Zoe promises she will not give up and goes to see David,
who says Michael died the moment they took off. He is furious because he continues to lose algae,
and he has already lost all his life's work anyway. Still stubborn, Zoe won't accept this and
decides to start teaching Michael how to climb the tether as a last-ditch effort to reach the tank.
Unfortunately Michael just can not get the hang of it, he keeps slipping down and falling, which ends
up with him hitting his forehead. Desperate, Zoe approaches Marina and David to ask them to let her
climb the tether, she also asks David to come with her since Michael can not do it. To her surprise,
David accepts, and he explains why: the first batch of algae has also died, meaning now only two
people will survive. The launch tank is their only hope. Minutes later, David and Zoe suit up and
begin the 450-meter climb. It is quite difficult at first and they have to make a great effort,
but the further up and away from the artificial gravity they get, the easier climbing becomes,
especially when they stop for a break. Halfway up they reach the solar array, where they have
to be careful because one wrong move could take down their ship's power permanently. The duo
climbs slowly and very carefully with the help of a rope, managing to make it across without
breaking anything. After a bit more climbing, they land on the other end of the ship, and Zoe is the
one to approach the containment with the tank with careful hops. After the containment door
falls into the abyss, Zoe taps into the tank and confirms the gauge goes over 500, meaning
they have more than enough oxygen for everyone. After reporting to Marina, David lowers a cylinder
with a rope, which Zoe grabs and connects to the pipe to fill it up. The seal is imperfect
and some oxygen leaks, but it is still enough. Once the canister is full, she sends it back up,
and David lowers the second one. Zoe quickly begins to fill it but suddenly an alarm goes off,
warning them of a solar storm approaching. Marina orders them to abort because if they are not back
in twenty minutes, the radiation will kill them. Zoe climbs out of the tank in a hurry,
leaving the second canister behind, meaning only three people will be surviving. She
begins to climb back, but when she crosses the solar array to join David, she loses control,
sliding fast toward the ship until she slams into it and accidentally loses the canister,
which disappears into the void of space. The duo goes back inside and after some awkward silence,
David points out that their only hope is the second canister still in the tank. Maybe after
the storm passes they can get it back, but Marina points out the storm will last hours and they will
be dead by then. Michael volunteers to climb through the radiation and sacrifice himself to
get the canister since this is his fault, but they know he is untrained and could never make
it. Marina can’t go because she has to pilot the ship, so David tries to volunteer next but Zoe
beats him to it. Zoe says her goodbyes to each crew member and leaves to start the climb. It
is even more difficult now with the solar storm slowly burning her face, but after lots of effort,
she manages to make it to the tank and retrieve the canister. She immediately puts it inside for
the crew to pick up, and Marina silently thanks her for her sacrifice. Now Zoe sits on top of
the ship, her skin burning and her breaths becoming labored as she takes in the sight
of stars and Mars in the distance, waiting for the radiation poisoning to do its thing.