The story follows a six-member crew aboard the International Space Station (ISS), where they encounter a returning probe from Mars that carries a soil sample potentially containing signs of extraterrestrial life. Having been in orbit for 30 years with a cumulative cost of $200 billion, the ISS is about to undergo a pivotal experiment. The capsule has been on its journey for eight months, but during its return, it gets struck by space debris, finding itself off course.
In a bold move, Rory Adams, an astronaut and engineer, risks his life by venturing outside the station to capture the capsule using the robotic arm of the ISS. His instructions are clear: if he fails to secure it, he must send the capsule into the vastness of deep space. With the ISS firing its thrusters to align perfectly, Rory successfully captures the capsule.
On the second day, the sample is transported to a specialized quarantine lab for detailed analysis. In this crucial phase, exobiologist Hugh Derry (played by [Dane DeHaan]) successfully revives a dormant cell from the Mars sample. Under a controlled environment of high CO2 levels and a glucose-filled medium, this dormant cell begins its miraculous revival, marking what seems to be the first undeniable proof of life beyond Earth. This organism soon evolves into a multi-celled life form that gets named “Calvin” by American school children, drawing its name from Calvin Coolidge Elementary School.
As events unfold, it’s revealed that astronaut David has been aboard the ISS for 473 days, facing severe muscle atrophy and radiation exposure. By day 12, Hugh discovers Calvin's remarkable ability to change cell specialization, morphing into muscle, neuron, and photo-sensory cells simultaneously. Calvin's growth is not just fascinating, but it also becomes an unsettling presence as it begins to interact with Hugh.
By day 25, an accident in the lab plunges Calvin back into dormancy, offering a momentary relief for commander Katerina. However, when Hugh tries to revive Calvin with mild electric shocks, it backfires tremendously as Calvin becomes hostile, attacking Hugh and escaping into the lab after consuming a lab rat.
The situation escalates when Rory Adams enters the lab to save Hugh, but Calvin latches onto his leg, leading to a gruesome demise after being locked in the room by physician David. Calvin, now a larger menace, breaches the lab in search of escape, while the crew's communication with Earth gets severed.
Mission commander Katerina Golovkina (played by Olga Dihovichnaya) attempts to fix the antenna in a spacewalk but becomes a victim of Calvin’s wrath, facing tragic consequences as she struggles to keep the creature out of the station.
With the ISS falling into a decaying orbit, the crew realizes that their only chance may be to contain Calvin by venting air from the station. However, as they attempt to reclaim their power and safety, the true horror of Calvin emerges when it attacks the remaining crew, leading to a frantic fight for survival.
The dire situation intensifies further as Earth sends a Soyuz capsule to retrieve the ISS, but this leads to chaos when Calvin attacks Sho Murakami (played by Hiroyuki Sanada) during attempts to board the rescue ship, resulting in catastrophic consequences.
In a desperate act of survival, David leads Calvin into an escape pod while allowing Miranda North (played by Rebecca Ferguson) to launch in another pod to safety. However, as Calvin engulfs David, the fate of both crewmembers hangs in the balance, culminating in a shocking conclusion where David finds himself encased in a web-like substance just as Miranda drifts into the unknown.
The closing scenes reveal the ominous outcome of their encounter with Calvin, leaving audiences to ponder the perilous implications of their exploration and the unforeseen consequences of awakening life from another world.
