Soviet spy Ladeynikov learns that in one of the pharmaceutical centers in a small resort town works a former German war criminal, Dr. Hass, who is finishing the creation of a deadly chemical gas RH development that he began during World War II, experimenting on POWs. Since Ladeynikov doesn't know Dr. Hass's appearance, Soviet intelligence recruits an actor, Ivan Savushkin, who, during the war, escaped from a prison camp where Hass was testing his gas. Together, they must identify and stop him before he finishes and unleashes his weapon of mass destruction.
| Actor | Role |
|---|---|
 Donatas BanionisKonstantin Ladeinikov | Konstantin Ladeinikov |
 Rolan BykovIvan Savushkin | Ivan Savushkin |
 Bruno FrejndlikhValery Petrovich | Valery Petrovich |
 Gennadiy YukhtinMuravyov | Muravyov |
 Jüri JärvetProfessor O'Reilly | Professor O'Reilly |
 Sergei KurilovPavel Bocharov | Pavel Bocharov |
 Ants EskolaSmith | Smith |
 Einari KoppelDrayton | Drayton |
 Vladimir ErenbergProfessor Born/Hass | Professor Born/Hass |
 Svetlana KorkoshkoEllis | Ellis |
 Leonhard MerzinFather Mortimer | Father Mortimer |
 Anda ZaiceKatherine | Katherine |
 Nikolay Zaseev-RudenkoNot listed | Not listed |
 Mikhail IvanovNot listed | Not listed |
 Stepan KrylovNot listed | Not listed |
 Heino MandriNot listed | Not listed |
 Vadim MedvedevNot listed | Not listed |
 Vytautas TomkusNot listed | Not listed |
| AAvgust BaltrusaitisNot listed | Not listed |
 Ants LauterNot listed | Not listed |
 Vladimir GreminNot listed | Not listed |