The movie is set in a dystopian future,
and the prologue reveals that after the cold war between Russia and the United States,
the International Space Station (ISS) was built.
This acted as a sort of peace treaty between the two countries.
The ISS is used as a research facility to make significant advancements in medicine,
technology and space exploration.
Astronauts from both countries live on it, and they have coexisted peacefully.
Plus, a special kind of rocket named Soyuz transports people from Earth to the ISS.
In the present day, we see an American astronaut named Kira aboard the Soyuz;
she is pretty excited to land on the ISS as it is her first trip here.
A veteran named Christian is also accompanying her after a short holiday on Earth.
Along the way, the mission control from both the US and Russia keep talking over the radio.
After hours of traveling, the Soyuz finally docks on the ISS, and when the door opens,
the astronauts are welcomed by their fellow researchers.
With the addition of Kira and Christian, the number of Americans in the ISS has increased to 3.
The 3rd astronaut is Commander Gordon, who is leading the operations for their country.
As for the Russians, there are also 3 people onboard, Weronika, Nicholai, and Alexey.
The latter 2 are revealed to be brothers.
The bond between the two groups is immensely strong, and they carry out most of their activities together.
After settling in, Kira has a small chit chat with Weronika, and the latter reveals that
she has been on this station for 50 days now.
She also teaches the new girl a Russian phrase, which translates to
‘The important thing is that we stick together.’
Gordon approaches Kira, and informs her that the internet here is pretty bad,
but she can get occasional signals every now and then.
There is a constant little humming sound in the ISS, and it is the life support engine.
If the sound goes out, that means that they are in trouble.
He also takes her to a separate room where everyone has a cabinet,
and she can store her personal belongings there.
After Gordon departs, Kira brings out some rats and keeps them in a special chamber;
she brought them all the way from Earth to conduct some tests.
Shortly after, the Russian, Alexey, joins her and they have a playful encounter.
Seeing the rats inside the chamber, Alexey reveals that they have conducted several tests
like these in the past, but they have always ended badly.
Later, Kira goes to the recreation room, where everyone seems to be having a fun time.
The 6 of them gather in a room later, where they share stories.
After a while, they decide to take Kira to the outermost dome of the ISS,
and they are amazed to see Earth from space, because only about 500 other people have seen what they
are seeing now.
From here, they can see earth with no borders and divisions; everyone's the same.
That night, Kira struggles to sleep as it’s the first time she’s trying to do so without gravity.
Weronika then comes to her room, attaching her with some belts, and she can now finally
get some sleep.
In the morning, the crew realizes that the computers are down.
This is not very uncommon so they don’t pay much attention to it.
As Kira goes to check her rats, she finds that they have injured each other badly.
Kira feels awful about it, so she goes to the dome of the ISS to have some alone time.
But then, she notices strange lights emitting from different parts of the earth.
Kira believes that it’s just some volcanoes erupting, and she calls the others to witness it.
However, when several other explosions occur throughout the earth, they realize that something
has gone wrong.
In the aftermath, the 2 sets of astronauts try to establish contact with their respective nationalities.
They want to know what’s going on down there on Earth, but the internet seems to be out.
As the tension inside the ISS grows, Commander Gordon suddenly receives a message on his computer.
It is from the control room back in Dallas; they ask him to remain silent as what they
are about to say is classified.
Then, in a shocking turn of events, they reveal that the US and Russia have engaged in an act of war.
The control room orders Gordon to cease all operations for now and take control of the ISS.
He has to do so by ANY MEANS NECESSARY!
Gordon is shocked by the revelation and he tries to ask further questions,
but the communications abruptly cut off.
Gordon then gathers his fellow Americans, and briefs them about the tragic news.
He asks them to keep it a secret, as they don’t know what the Russians are up to.
The lack of information makes them very anxious, but they have no choice but to wait until
the communications are back on.
A while later, they head over to the Russian side of the control room.
The bad news is that almost all of their devices have stopped working due to a malfunction.
And if they can’t contact their base within the next 24 hours, they will lose gravity and eventually fall.
They can’t even use the Soyuz to go back to earth as it can only transport 2 people at once.
After some research, Nicholai claims that the outermost antenna has been broken.
Now, someone will have to go out there, and manually repair it.
In the next scene, Gordon prepares for the mission, and Weronika helps him put on his spacesuit.
It is revealed that the two are in a romantic relationship.
Christian then approaches Gordon, and asks if he doesn’t find it odd that none of the
Russians are volunteering to do this.
However, Gordon asserts that he trusts Weronika and the Russians, before eventually making his way out.
As soon as he exits the ISS, he comes across a horrific sight; large portions of the earth
have been set ablaze by nuclear weapons.
Kira talks to him over the intercom, but he doesn’t tell her about it, and simply asks
her not to let the others go near the window.
The two then engage in conversation, while Gordon tries to remain composed as he completes
the mission in the face of the terrifying state of the earth.
Elsewhere, Alexey goes to Christian’s room, and requests to use the bathroom.
But when Christian ventures off to somewhere else, Alexey comes out of the bathroom.
He finally reveals his true intentions, and it turns out he’s here to sabotage Gordon’s radio.
Alexey gains access to the main circuit, and proceeds to cut a wire.
He hesitates for a long time as he doesn’t want to go down that line, but in the end,
he reluctantly does it, causing Gordon to lose communication with Kira and the ISS.
This sends the Americans in panic mode as their commander is now hanging on for dear life.
Weronika also grows worried for her lover and she tries her best to contact him,
but to no avail.
Outside, Gordon is left alone on his mission to fix the antenna.
The ISS is designed in such a way that its parts can be moved from the control room,
and this can make movement possible from one place to another.
But since no one can hear Gordon now, he can’t tell them about his exact location.
At one point, he has to reach a platform, but his tether doesn’t allow him to do so.
So, he reluctantly detaches his tether, and proceeds to the antenna on his own.
After a while, Gordon eventually reaches the antenna, only to learn that it looks completely fine.
This makes him realize that Nicholai lied to him, and he tries telling his colleagues about it,
but no one can hear him.
Inside the ISS, we see Nicholai controlling the ‘arm,’ which is a robotic mechanism used for transportation.
He cunningly takes it near Gordon and strikes him with it, causing him to tumble down the platform.
Shortly after, Christian peeks through the window and sees the commander flying outside.
This alarms the group, and they immediately decide to pull his tether.
But to their dismay, they learn that he had already detached it prior to his freefall.
That night, Kira tells Christian that she believes that Gordon is still alive,
and wants to go out there to save him, but Christian is sure that he’s dead by now.
He urges her to stay, as he doesn’t want to be left alone among the Russians.
In the other room, the brothers finally tell Weronika about the situation on earth.
Turns out they’ve also been instructed to take control of the ISS at all cost.
They reveal that they cut off Gordon’s radio, but hide the fact that Nicholai was the one
who pushed him off the platform.
Hearing all this, Weronika is heartbroken, and she chastises them for their decisions.
She then begs Alexey to save Gordon, as he may still be alive, but Alexey can’t do
anything to reverse it now.
Meanwhile, Christian believes that the Russians also received orders to take control of the ISS,
and they have struck first.
Their conversation is abruptly interrupted by Weronika, who wants to talk to Kira in private.
Christian doesn’t want to leave her alone, but upon some insisting, he obliges.
Once he’s out of sight, Weronika asks Kira for help, and claims that she can’t trust
anyone but her right now, as she’s new here.
Weronika reveals that Alexey is working on some advanced compounds which can be used
to cure radiation.
Since the earth is under the threat of war, these compounds can prove very valuable right now.
Both of them then share that their respective countries have ordered them to take control of the ship.
Now that they’re on the same page, Weronika gives Kira the keys to Alexey’s locker,
where he keeps his cure compound notes.
She also instructs her to open Node Zero, which contains more important files and samples.
Weronika wants her to retrieve all of them, and return back to earth in the Soyuz.
This way, she can help a lot of injured people who are in desperate need of help.
Kira is scared of traveling alone, but with the fate of the entire earth in her hands,
she agrees.
In the next scene, Weronika grabs a blowtorch to set up a distraction.
She opens the oxygen valve, and threatens to burn the entire station down if anyone comes near her.
The Russian brothers try their best to calm her down, but she just won’t listen.
On the other side of the ship, Kira has reached Alexey’s locker, but Christian also arrives
there and he’s surprised to see her rummaging through the lockers.
Kira simply asks him to help her find Node Zero, but shockingly, he replies that there’s
no Node Zero in the ship.
This makes Kira realize that Weronika lied to her, so the two rush to confront her.
In the meantime, the Russian brothers politely try to make her understand that they should
stick together, but she doesn’t listen.
Just then, Christian arrives and slams her head with a large container, knocking her unconscious.
The Russians are enraged to see this, but Christian claims that he was only helping
as she could have blown up the entire station.
After the Americans flee the scene, the brothers try to resuscitate a motionless Weronika.
Unfortunately, despite their best efforts, she doesn’t come back to life.
The younger brother, Alexey believes that she died because of their actions,
but Nicholai holds the Americans responsible for it.
So, to take revenge, he grabs a screwdriver, and proceeds to find them.
A while later, as Alexey is lost in his thoughts, he notices on the computer screen that Gordon
is still alive outside.
This fills him with joy, and he decides to atone for his earlier mistake.
He then maneuvers the robotic hand, and somehow leads Gordon inside the ISS.
After this, Alexey grabs a scared Kira, and hides her in his room.
He then approaches his brother and urges him to stop all this madness,
as they have to stick together right now.
But Nicholai ignores him and he eventually finds Christian hiding in the nearby junk,
and starts attacking him.
But before he can cause any serious damage, Commander Gordon shows up out of nowhere and intervenes.
When he learns that his lover Weronika has been killed, he goes absolutely bonkers.
So, he locks himself with Nicholai in a room, and launches an attack on him with a drilling machine.
After a lengthy low gravity battle, Nicholai manages to snatch the drilling machine and
stab Gordon in the abdomen.
But he is also pierced in the neck by his own screwdriver.
This causes both of them to die in each other’s arms.
In the aftermath of this horrific incident, all the remaining astronauts are left shattered.
They were 6 just a day ago, but now the number has been reduced to 3.
At night, while Kira is roaming around the Russian section of the ISS, she checks the
altitude warning of the ISS as it gets closer to the earth.
Here, she suddenly spots the words ‘Node 0’.
Turns out Weronika wasn’t lying after all; she actually wanted Kira to retrieve the notes and escape.
Enraged that she was lied to, Kira goes to confront Christian in his room.
She doesn’t find him, but learns that he’s actually preparing to escape in the Soyuz,
alone with the samples.
Then, all of a sudden, the humming sound inside the ISS stops, which means that they’re in danger.
A panicked Kira then rushes to the kitchen, where she finds Christian nonchalantly making some sandwich.
Alexey is also there, carrying out some personal work.
Kira notices that Christian has a knife on him, so she tries to distract him with small talk.
She also keeps signaling to Alexey about the life support that has been turned off.
After a while, Christian requests to speak with Kira in private,
so he asks Alexey to leave the room.
The latter obliges, but as he proceeds to walk away, Kira utters the same Russian phrase
that Weronika had taught her earlier.
‘The important thing is that we stick together’.
Christian, who understands Russian, gets to know what she’s implying.
He realizes that he has been exposed so he finally reveals his intentions.
He was the one who froze the life support, but he knows how to reverse the process.
In response, Alexey says ‘So do I’.
Subsequently, Kira and Christian go for the knife.
Christian tries to attack her with the knife, but Alexy blocks it with his own hands.
As they struggle, Kira manages to put Christian on a strangle hold.
She pulls him with all her strength and eventually kills him.
After the incident, Kira patches up Alexey’s wound, and he reactivates the life support.
The communications also come back online, which means that the ISS is finally out of danger.
Both the Americans and Russians receive a lot of messages from their respective bases.
They want to know the status of the ISS, but Kira and Alexey refrain from replying to them.
In the final scene, they suit up, and get inside the Soyuz along with all the important notes and samples.
The Americans and Russians learn that the rocket is on the move, so they inquire about
the occupants.
They are ready to help their respective people once they land, but Kira and Alexey remain silent.
The two are heading to earth, but not sure where on earth.