"The inhabitants of Ganymede need to find mates from another world or they will become extinct. They soon discover a suitable breeding stock amongst the females of planet Earth."
John Saxon
as Dr. Jack Costain
Patricia Haines
as Ann Barlow
Alfred Burke
as Detective Supt. Hartley
Maurice Denham
as Dr. Morley
John Carson
as The Major
Ballard Berkeley
as Cmdr. Savage
Stanley Meadows
as Det. Tom Grant
Barbara French
as Joyce Malone
Robert Crewdson
as Medra
Aubrey Morris
as Thorburn
Jack Watson
as The Sergeant
Tony Wager
as Pvt. Higgins
David Gregory
as Pvt. Jones
Marianne Stone
as Madge Lilburn
Warren Mitchell
as Reg Lilburn
Geoffrey Lumsden
as Col. Davy
Douglas Livingstone
as 2nd R / T soldier
Tom Gill
as Police Commissioner's secretary
Vincent Harding
as First R/T Soldier
Romo Garrara
as Lieutenant
John Sherlock
as TV Newscaster
Frank Crisp
Novel
John Gilling
Director
Jim O'Connolly
Screenplay
Philip Barnikel
Editor
Stephen Dade
Director of Photography
Joyce James
Hairstylist
Johnny Gregory
Original Music Composer
John I. Phillips
Executive Producer
Bunty Phillips
Makeup Artist
Ronald Liles
Producer
Harry White
Art Direction
Barbara Hopkins
Sound