Russia, 1983 – Cold War tensions at their peak. A terrifying scene is discovered at the landing site of spacecraft Orbit-4. The commander is dead, the flight engineer in coma. The third crew member, Valery Basov, has survived, but he has lost his memory from the horrific experience and cannot shed light on the cause of the accident. In a secluded government facility, under the vigilant watch of armed guards, psychologist Tatiana Klimova must cure the astronaut's amnesia and unravel the mystery. In the process, she learns that Orbit-4 may have carried back an alien parasite that threatens to consume them all.