A good doctor is out to stop his evil doctor brother from blackmailing his patients.

Curd Jürgens
as Dr. Jan Diffring

Christiane Rücker
as Margot Rau

Heinz Reincke
as Willi Nippens

Marianne Hoffmann
as Karin Steffen

Fritz Wepper
as Hein Jungermann

Monika Zinnenberg
as Gerda Heske

Friedrich Schütter
as Siegfried Gersum

Suzanne Roquette
as Elisabeth Langhoff

Michael Conti
as Helmut Weiher

Astrid Fournell
as Bärbel Harms