In a small English village everyone suddenly falls unconscious. When they awake every woman of child bearing age is pregnant. The resulting children have the same strange blond hair, eyes and a strong connection to each other.

George Sanders
as Gordon Zellaby

Barbara Shelley
as Anthea Zellaby

Martin Stephens
as David Zellaby

Michael Gwynn
as Alan Bernard

Laurence Naismith
as Dr. Willers

Richard Warner
as Harrington

Jenny Laird
as Mrs. Harrington

Sarah Long
as Evelyn Harrington

Thomas Heathcote
as James Pawle

Charlotte Mitchell
as Janet Pawle