Roddy McDowall

Eric Kardin

Kristine Miller

Marlina

Harry Lauter

Franz

Rand Brooks

Captain Giorg Nicholoff

Byron Foulger

Professor Kardin

Murray Alper

Nicholas

Marc Krah

Double Agent on Train

Kate Drain Lawson

Mrs. Krechow

Michael Vallon

Old Man on Train Station

Effie Laird

Scrubwoman

Glen Vernon

Student

Fred Kohler Jr.

Soldier

Bob Peoples

First Lieutenant (uncredited)

Gil Perkins

First Organizer (uncredited)

Fred Krone

First Student (uncredited)

Wesley Barry