At 600 km above planet Earth, the temperature fluctuates between +258 and -148 degrees Farenheit.
There is nothing to carry sound.
No air pressure.
Life in space is impossible.
The silence builds to loud noise and the title is displayed before sudden silence and a shot of Earth from space. The Explorer Space Shuttle floats lazily 370 miles above the Earth’s surface. Veteran astronaut Matt Kowalski propels above it, strapped into an experimental propulsion pack. He radios his compliments down to Houston before regaling the control room with the story of his trip to Tijuana from when his wife left him while he was on his first spacewalk. Houston reminds him that most of the workers down on Earth have heard the story, before congratulating Matt on his upcoming retirement; this will be his last spacewalk. As he zips around in the propulsion pack, Matt takes it all in.
Below him, two other astronauts work on the shuttle. Shariff Dasari, a flight engineer, gleefully jumps around on his tether – thoroughly enjoying the weightlessness. Nearby, on the docked Hubble Space Telescope, medical engineer Dr. Ryan Stone diligently works on repairing a faulty transmission card. Houston informs her that they are not receiving a signal before asking her to provide a new estimate on how long repairs should take: she needs sixty more minutes.
Matt zips over to Ryan and asks her if he can be of some assistance. He playfully flirts with her, asking about her training and complimenting her blue eyes. Stone laughs and claims her eyes are brown. Kowalski then laments that he will not be breaking the record for longest spacewalk before he retires – a personal career ambition. Houston confirms that Matt will fall shy of the current record – but Matt decides to take his mind off it by telling a story about his time in New Orleans while he assists Ryan with unscrewing the panel. A bolt floats away from the structure and Matt hops out after it – a safety tether catching him as the line goes taut – closing his hand around the floating bolt. Ryan apologizes, claiming that she is used to a basement lab where things fall to the floor. Before Matt can complete his story, Houston sends an urgent message: the astronauts need to return to the ship immediately because a cloud of satellite debris is hurtling right for them at over 50,000 miles per hour.
Matt fires his way back towards Shariff and the Explorer while Houston explains: a Russian satellite has self-destructed and the resulting debris cloud is hurtling towards the shuttle – which lies directly in it’s orbit. The debris hurtles forward through space towards the shuttle as Matt turns around to recover Ryan. Just as he reaches her, the first bits of debris begin to pepper the Explorer – striking Shariff and sending him off into space, the only thing catching him is the tether. The storm of debris rips through the ship and destroys the structure, sending Ryan off into the void. Matt, shielded by a large chunk of the structure, continues issuing commands to Ryan – insisting that she detach herself from the structure or else be carried too far from the shuttle. Already he cannot see her anymore. Stone complies and releases the strap only to be flung even further out into space.Ryan quickly tumbles away through the vast expanse of space with no control over her movements, the slightest one with the potential to leave her spinning out in space forever. Matt continues to radio instructions while she begs for assistance – ordering her to give him any information she can that can help him locate her position – but she’s spinning too fast to observe her environment. As she starts to slow down, Matt’s voice cuts out and she’s left floating forward, although she does manage to see the International Space Station in the distance. Oxygen dropping dangerously low, Ryan panics, breathing heavily and calling out despite not receiving a transmission. After a few tense moments of Stone desperately trying to signal with her light, her radio crackles to life – Matt, using his propulsion pack, has found her. He blasts forward, colliding with her and tethering her to him so that he can tow her back to the ship. After recovering Ryan, he transmits his radio message to Houston but receives no response. Ryan asks him what the point of radioing into the dark is and Matt simply says that just because they can’t hear Control doesn’t mean Control can’t hear them – it could just save their lives.
The duo begin their return towards the shuttle when Matt sees a space suit floating below them – Shariff, removed from his shuttle tether as well. Matt guides the propulsion pack towards Shariff and orders Ryan to grab him. Looking at Shariff, she sees a chunk of debris ripped through his helmet – leaving a hole through his face through which she can see clean through. She looks away, noticing for the first time a laminated photo tethered to Shariff’s suit of his family down below.
Arriving at the wreckage of the ship, they see that the hull was breached and the rest of the crew died from being exposed to the freezing vacuum of space. With life support running dry, Matt makes their next move clear: they need to get to the International Space Station nearby. Doing some quick calculations, the pair determines that they have 90 minutes to get there before the debris cloud completes its orbit around the planet and catches up to them again – bigger than before as it adds more satellite debris as it destroys other satellites in its path.As Ryan continues to note her dwindling oxygen supply, Matt tries to calm her down by asking her about her normal life on Earth and if there is anyone thinking of her. Ryan proves evasive before Matt’s prodding results in a quieting confession: years prior, her four year old daughter, Sarah, had an accident on the school playground and died when she hit her head too hard. Stone then reveals that every day after work at the hospital she drives and listens to the radio to avoid thinking about it. Matt is startled but doesn’t respond and Ryan looks out at the Earth, lost in her own head.
The ISS pulls into view but there are clear signs of structural damage from the debris strike. The pair notices that one of the Soyuz re-entry modules of the ISS is gone – the crew have abandoned the station. The other Soyuz has been damaged in the debris strike, resulting in a parachute having been deployed and currently entangled around the station. Matt tells her that while it can’t bring them back to Earth, they can use it to get to a nearby Chinese space station, the Tiangong-1. Kowalski then then checks his propulsion pack: there are only two bursts left if they are lucky. At this time, Ryan's tank runs out of oxygen but she has a small amount in her suit.
As their oxygen supplies begin to bottom out, Matt fires the remaining bursts towards the ISS. As the two blast forward, they strike the ISS and roll forward – tumbling away from one another. Ryan successfully catches on to part of the ISS’s paneling but Matt isn’t so lucky, bouncing off the paneling and out to space. Their connection tether snaps tight, ripping Ryan free of the ISS and dragging her out into space. As they are pulled out into space, Ryan’s leg catches on the parachute cords of the Soyuz module – keeping her attached to the ISS. But Matt sees the connection is tenuous at best – his momentum from continuous deceleration is going to pull her free and they will both die. Ryan realizes that Matt is going to detach his suit from the connection tether and begs him not to but Matt tells her she has to get back to the planet. He disconnects the tether and floats off.
As Ryan is propelled back towards the ISS by the disconnect, Matt continues to tell her what to do. Her space suit begins blaring alarms – she has no oxygen remaining, only carbon dioxide. Kowalski instructs Ryan to climb up the side of the ISS to the airlock roughly 40 feet away, and makes her promise that she’s going to make it. Instead, Stone claims that she intends to take the Soyuz to and retrieve him first. He tells her that ship has sailed because he has too much of a head start on her and that jokes that he’ll hold the record for longest spacewalk for a long time. Stone then says that she will make it for him. Kowalski then asks if she is attracted to him, claiming that many women say he has beautiful blue eyes. Stone says that he has beautiful blue eyes and Kowalski claims that his eyes are brown. Kowalski tells Stone that the sun on the Ganges is beautiful. Ryan is now only breathing the carbon dioxide in her suit, causing her to lose consiousness. In her oxygen-deprived state, she reaches out to Kowalski in an attempt to grab him, her vision distorted and her mental state slowing as she loses consiousness from hypercapnia. Ryan eventually is forced to jump into space towards the airlock, and she barely reaches it. She opens the airlock just in time and activates the decompression unit – flooding the chamber with oxygen. She strips her suit and breathes large gulps of air as she floats. She slowly curls into the fetal position and falls asleep, relieved to be alive.
After taking a few minutes to recover, Ryan starts to make her way through the ISS. Despite the damage, the oxygen atmosphere is still intact. She passes by sparking wires which ignite balls of fire that float through the pure oxygen environment. Ryan fails to notice this because she is too preoccupied to contact Kowalski. She quickly puts on a headset and contacts Kowalski, who isn't responding. At first she chastizes him, claiming that now is the only time during the whole mission where he stopped talking, but then she asks him to continue his Mardi-Gras story, begging him to tell her what happened with the hairy guy. Kowalski still doesn't reply and she is forced to transmit to Houston that she is the sole survivor of the mission, with Kowalski having apparently succumed to carbon dioxide poisoning in his spacesuit. She then looks somberly out the window at Earth, so close yet so far away. However, it would seem that the ISS, her sanctuary, may be her tomb. The sparks from the exposed wiring have started a massive fire inside the ISS, which is quickly engulfing the entire station, making her sanctuary a tomb. Ryan grabs a fire extinguisher and tries to fight the inferno, but the lack of gravity causes the extinguisher's recoil to push her into a wall, bruising and cutting her face. She loses consiousness for a moment as her blood drips into space, but luckily is able to wake up and race past the fire, making it into the second Soyuz capsule just in time as the inferno engulfs the node she was in. Stone has also taken the fire extinguisher with her in case a blaze should erupt inside the Soyuz.
Ryan glances at her watch and realizes that she has a mere seven minutes to escape the ISS before the debris completes another orbit and wipes the remainder of the station out. She fires the thrusters and the capsule lurches free – away from the ISS before jerking to a stop suddenly. The parachute cables keep the Soyuz anchored to the ISS. She quickly dresses into a spare spacesuit and goes outside the Zvezda Module and begins releasing the parachute cables from the capsule as the debris strike arrives, blasting the ISS – deflected narrowly away from Ryan’s Soyuz. As the ISS is destroyed, Ryan scrambles back into the Soyuz and fires it away from the debris, remarking: "I hate space".
Ryan resets her watch to 90 minutes and begins setting up the Soyuz’s flight path to line it up with the Chinese space station. When she presses the fire button, she realizes that she is out of fuel. Stone nearly has a breakdown after smacking the equipment, but eventually just stops doing anything and wonders what to do. Having stayed in the capsule for some time, and already suffering from hypercapnia, Stone begins feeling dizzy from carbon dioxide poisoning, realizing that she will die unless she gets help fast. Desperate for some sort of assistance, Stone tries to use the radio as a last resort but only manages to stumble upon the frequency of a ham radio belonging to a Greenlandic fisherman who does not speak any English. Stone at first believes it to be a person from the Chinese space station but realizes he is calling from Earth after hearing his dogs bark. Stone gives up hope after she realizes the man cannot understand her pleas. Wanting some sort of accompaniment, she asks him to make the dogs bark and after barking along with them, she breaks down crying, claiming that she is going to die and knowing this terrifies her. Ryan asks him to say a prayer for her as she is stuck in space and will be torn apart by the debris field with no one to know she survived. However, when Stone hears the man cooing his baby with a lullaby, she remembers how she used to sing to her baby and realizes that she wants to die, so there is no more pain over the loss of her child. Accepting that she will die, she turns off the oxygen flow to the cabin and turns off the lights for a painless suicide. Stone is slowly drifting to a deep sleep to succumb to oxygen deprivation when there’s a knock on the door from an astronaut gesturing outside!As she starts to resist, he turns the handle and opens the hatch. Quickly swinging in, the astronaut plops down beside her and removes his helmet – it’s Matt! He grins broadly, reactivating the oxygen flow to the cabin and tells her that he has beaten the spacewalk record. Ryan asks him how he managed to get back to her and Matt explains: having tinkered around with the propulsion pack, he managed to get a few more bursts out of it to guide him back her way. She tells him that the fuel’s all gone but he points out that the capsule has re-entry rockets for landing. He tells her that she can pilot her way to the station that way. Matt looks over everything and realizes that she was trying to kill herself, telling her that losing a daughter makes everything harder but that’s not a reason to want to die. He concedes that if she really does want to give up, all she has to do is stay there – shutting down the air flow once more. Delirious from hypoxia and barely able to speak, Stone asks how he got there and he tells her that it's "a hell of a story" before telling Ryan that "it's time to go home". She turns around to look at Kowalski only to see that he is gone, revealing that he was a hallucination resulting from severe oxygen deprivation. Ryan gasps back to consciousness, realizing that she’s still alone. She reactivates the air flow to the cabin and as the oxygen levels rise she begins to recover remembering what her subconscious was trying to tell her by manifesting Kowalski; that the re-entry rockets run on a separate fuel tank and she can still make it to the Tiangong. With renewed determination, she fires the thrusters and shoots off towards the Chinese station on momentum.
As the Soyuz capsule flies forward, Ryan sees that the station has been greatly damaged by the debris and is sinking into the atmosphere. Stone also notices that she will miss the station by several meters. Retrieving the fire extinguisher she used to fight the fire on the ISS, she blasts open the airlock with pyrotechnics via explosive decompression and is thrown out into space. Using the fire extinguisher to propel herself towards the Chinese space station, she slams into it and manages to hang on as the Tiangong drops faster through the Earth's atmosphere and begins a rapid descent. The debris field reappears in the distance, racing towards her as she begins her climb to the airlock while the station begins to break apart.
The debris strike slams into the Chinese space station, shredding it and rapidly forcing the station out of its orbit towards a re-entry. Ryan climbs into the airlock, determined to reach the Shenzou. She reaches the capsule in time just as the station starts to plummet through the upper atmosphere, 150 kilometers above planet Earth. Stone struggles to make sense of the symbols – pressing random buttons to see if she can initialize the re-entry protocol. Luckily because the Shenzou is pretty much the Chinese Soyuz, she is able to piece together what she needs to allow the Shenzou to disengage its locks and undock from the surrounding Tiangong station as what's left of it hurtles through the Earth's upper atmosphere 120 kilometers above planet Earth at over 25,000 feet per second. Ryan says a prayer to Matt and asks him to tell her daughter that she loves and is proud of her. She also tells Houston over the radio that she has a newfound will to live and whether she lives or dies, she is ready for whatever comes her way.The capsule explodes forward, taking the lead of the debris field as the station falls apart with each passing second – erupting into lines of fire across the sky. Ryan closes her eyes and puts on the helmet to her spacesuit The Tiangong continues breaking apart when the gravity takes hold and drags it down to the Earth's lower atmosphere, 70 kilometers above the surface. Luckily the parachute is activated 10 kilometers above the surface, slowing the capsule and allowing it to land gently in a lake of water somewhere in the American southwest.
The capsule hits the water and floats for a moment – radio cracking to life as Houston is finally able to make contact, promising a rescue. However an electrical fire breaks out, forcing Stone to escape the Shenzou immediately. She ejects the hatch and the Shenzou rapidly fills with water, and struggles to breathe. For a moment it seems like she will drown and the weight of the capsule and parachute quickly drag it to the bottom. Stone tries to swim to the surface, but the eighty pound spacesuit pins her to the bottom of the lake. Stone is forced to frantically strip away the heavy suit to allow her to make a desperate flight to the surface.
Ryan bursts out of the water and floats on the surface, taking a moment to catch her breath where she sees the remaining debris of the Tiangong station completing its own re-entry and burning up across the sky. Stone is able to swim to shore where she collapses momentarily on the beach, laughing and gripping the sand in her hands, happy to be on land again. Forcing herself to stand and walk to await rescue, she takes her first shaky steps on dry land, acclimating herself to existing in the Earth's gravity.