Spaceships Argos and Galliot carry crews of explorer-scientists to Aura, a distant planet which transmits radio signals and has an oxygen atmosphere. As Capt. Mark Markary of the Argos lands his ship, the crew members go berserk and attack one another. Later, they find the wreckage of the Galliot with the mutilated bodies of its crew, who were apparently killed fighting among themselves. The crew of the Argos find no signs of life on Aura, but Professor Karan speculates that the planet is inhabited by invisible minds seeking to control the wills of the visitors. That night, the bodies of the Galliot 's crew are seen to move through the planet's eerie mists; and one by one Mark's crew are killed or disappear. Mark captures one of the missing crew members and discovers that his body is inhabited by a being from Aura, whose survivors hope to leave their dying planet in the visitors' spaceships. The survivors of the Argos foil the Aurans' attempt to disable their craft, and Mark escapes with his assistant, Sanya, and second-in-command, Wess. However, he perceives that his companions have been vampirized by the Aurans, who now prepare to land on an unknown planet--Earth. [Sources disagree on the precise ending of the film; according to some sources, Mark and Sanya escape unharmed.]