American satellite X-117, carrying a chimpanzee, has unexpectedly fallen back to earth after entering a part of the stratosphere known as "the flame barrier", which encircles the earth at an altitude of 200 miles. Howard Dahlman (Dan Gachman), a rich businessman and ardent amateur space program enthusiast, went into the Mexican jungle to recover the satellite but never returned. His wife Carol (Kathleen Crowley) sets out to find him.