A human colony ship lands on a planet where all life forms are part of a single organism with a unified consciousness. The organism tries to make the humans join its collective by inducing pregnancy in all the female animals and altering their offspring. The colony ship’s captain discovers this and destroys his ship with all aboard. Later, a research ship from Earth investigates the planet and finds out the truth. They try to return to Earth, but they unknowingly carry a stowaway creature that is part of the organism and wants to spread its consciousness to all life on Earth.