Apollo 17 was the last U.S.-sponsored lunar voyage -- or was it? Hours of found footage, classified for decades, point to a subsequent moon mission -- Apollo 18 -- that ended very badly. Astronauts John Grey (Ryan Robbins), Nathan Walker (Lloyd Owen) and Benjamin Anderson (Warren Christie), on a mission to install radar scanners, discover a Soviet space capsule nearby. The men also discover a dead cosmonaut, and unfortunately for them, learn how he died.
Astronaut Sam Bell's (Sam Rockwell) three-year shift at a lunar mine is finally coming to an end, and he's looking forward to his reunion with his wife (Dominique McElligott) and young daughter. Suddenly, Sam's health takes a drastic turn for the worse. He suffers painful headaches and hallucinations, and almost has a fatal accident. He meets what appears to be a younger version of himself, possibly a clone. With time running out, Sam must solve the mystery before the company crew arrives.