Four isolated astronauts in the lunar mining base Ark suffer a meteor storm. Colonel Gerard Brauchman sends Ava Cameron to repair a wing that is full of carbon monoxide. Dr. Lance Krauss warns that the gas may cause paranoia and hallucinations. While inspecting the damage caused by the meteors, astronaut Ava Cameron discovers spores contained in one of the fragments and brings them back to the base for investigation and Dr. Krauss finds that there are spores attached to the meteor. Ava accidentally cuts her finger in a sample but she hides the cut from the doctor. Soon Ava gets pregnant and delivers an alien offspring. Brauchman and Kraus believe that Ava is delusional. The offspring bites the crewman Bruce Johns and produces a clone of him.