Engineer Dukalsky arrives from Moscow on the instructions of an underground anti-Soviet center to the Baltic Shipyard in order to take possession of the blueprints of a powerful ship engine. The pest meets the author of the project - a young and incorruptible self-taught master Ivanov. After a series of unsuccessful attempts to buy out or steal the drawings from the author, Dukalsky decides to take Ivanov with him. Criminal Investigation Officers will attack the trail of criminals.
| Actor | Role |
|---|---|
 Nikolai SimonovIvanov, factory worker and inventor | Ivanov, factory worker and inventor |
| PPetr KuznetsovDukalskiy, engineer from Moscow | Dukalskiy, engineer from Moscow |
| NNatalya RazumovaNastya, Ivanov's fiancée | Nastya, Ivanov's fiancée |
 Sergei TroitskyKraft, technical office representative | Kraft, technical office representative |
| PPetr ShidlovskyBabkin, jewelry shop owner | Babkin, jewelry shop owner |
| AAlexandr RzheshevskyImportant man | Important man |