Five men are stationed on a space satellite, tasked with monitoring Earth and each other, equipped with nuclear weapons to deter aggression. Their routine is disrupted when they discover an alien spaceship moored nearby. The crew, consisting of representatives from the U.S., Russia, France, England, and India, debates whether to investigate the ship. They ultimately decide to explore it together, finding it empty but perplexing. As they return to the satellite, tension rises over the possibility of an alien presence. Lal, the Indian crew member, suggests that the pilot might be invisible, leading to paranoia among the men. They agree to keep constant watch over one another, fearing that one of them could be an alien in disguise. This fear escalates when Lal mysteriously dies during a spacewalk, leading to speculation about the alien's influence. The remaining crew members, now four, continue to grapple with their paranoia. They operate in pairs to maintain vigilance. The situation deteriorates further when Lasseux, the Frenchman, claims to have shot Golovunoff, the Russian, believing him to be the alien. However, Lasseux himself begins to exhibit strange behavior, leading Gregson to shoot him as well, convinced he is the alien. With only Beveridge left, Gregson confronts him, suspecting he too might be the alien. In a tense standoff, Gregson is shot by Beveridge, who then reveals his own alien nature. The story concludes with the satellite's nuclear arsenal being unleashed upon Earth, leaving the fate of humanity uncertain. The narrative explores themes of paranoia, trust, and the fragility of human relationships in the face of existential threats.
By Randall Garrett · First published 1970 · Genre: Science Fiction, Thriller, Mystery