A woman is kidnapped by a stranger on a routine flight. Threatened by the potential murder of her father, she is pulled into a plot to assist her captor in offing a politician.
Usred Hladnog rata znanstvenik Jan Beneš (Jean Del Val) bježi s Istoka na Zapad u čemu mu pomaže američki obavještajac Grant (Stephen Boyd). No, neposredno nakon slijetanja zrakoplova Benešovo je vozilo napadnuto te nesretni znanstvenik završi u komi. Kako bi ga spasili njegovi domaćini pod vodstvom generala Cartera (Edmond O'Brien) organiziraju dotad neviđenu operaciju. Na čelu s agentom Grantom formiraju posadu koja će u podmornici smanjenoj na mikroskopsku veličinu biti ubrizgana u Benešov krvotok kako bi stigla do njegovog mozga i ondje uklonila opasni krvni ugrušak. Uz Granta tim, među ostalima, čine i dr. Michaels (Donald Pleasence) te pomoćnica Cora (Raquel Welch) koji pred sobom imaju gotovo nemoguć zadatak jer učinak smanjivanja traje samo sat vremena. Nakon toga, životi su im svima ugroženi.
On a flight transporting dangerous convicts, murderer Ryan Weaver manages to break free and cause complete chaos throughout the plane. As various people on board fall victim to Weaver, it is ultimately down to flight attendant Teri Halloran to keep the aircraft from crashing, with on-ground support from an air traffic controller. While Halloran struggles to pilot the plane, Weaver continues to terrorize the surviving members of the crew.
As the plane slowly makes its descent, a young couple is faced with their differences through sudden pockets of turbulence.