In order to save an assassinated scientist, a submarine and its crew are shrunk to microscopic size and injected into his bloodstream.
Stephen Boyd
Raquel Welch
Edmond O'Brien
Donald Pleasence
Arthur O'Connell
William Redfield
Arthur Kennedy
Jean Del Val
Barry Coe
Ken Scott
Shelby Grant
James Brolin
Brendan Fitzgerald
Brendon Boone
James Doohan
Kenneth MacDonald
Christopher Riordan