Four explorers are summoned to Peru by the brilliant physicist Dr Thorkel. They discover a rich source of radium and a half-mad Thorkel who shrinks them down to one-fifth their normal size when they threaten to stop his unorthodox experimentation.
Albert Dekker
as Dr. Alexander Thorkel
Thomas Coley
as Bill Stockton
Janice Logan
as Dr. Mary Robinson
Charles Halton
as Dr. Rupert Bulfinch
Victor Kilian
as Steve Baker
Frank Yaconelli
as Pedro
Paul Fix
as Dr. Mendoza
Frank Reicher
as Prof. Kendall
Jane Webb
as Woman
Billy Wilkerson
as Silent Indian
