Starship C57D travels to planet Altair 4 in search of the crew of spaceship "Bellerophon," a scientific expedition that has been missing for twenty years. They find themselves unwelcome by the expedition's lone survivor and warned of destruction by an invisible force if they don't turn back immediately.

Starship C57D travels to planet Altair 4 in search of the crew of spaceship "Bellerophon," a scientific expedition that has been missing for twenty years. They find themselves unwelcome by the expedition's lone survivor and warned of destruction by an invisible force if they don't turn back immediately.