Carl Stone returns from Washington to a top-secret desert base only to witness a terrifying creature drag a young woman into the night. His reports are met with hostility and disbelief, as base director MacDougal and his aide Glines accuse him of treason and murder. Plunged into a waking nightmare of suspicion, Stone discovers that the entire base has been subjected to a mind-distorting transmitter operated by an alien intelligence. The entities require Earth's krypton to fuel their ships, a process that would strip away the planet's atmosphere and extinguish all life.
As the aliens capture the base and take hostages, Stone must navigate a maze of paranoia and violence to disable the machinery. With the help of an erratic survivor, he manages to sabotage the alien apparatus and rally the base's defenses. Ultimately, Stone uncovers a traitor among the leadership, resolving the crisis just as the alien sphere retreats into the stars.
