Pirx, an experienced pilot, is hired to go on a top-secret mission to evaluate some 'nonlinears' (an experimental model of android) for use as crewmembers on future space flights. Pirx and this intriguing crew are sent out to launch two satellites into the rings of Saturn, but he is determined to find out and identify a hostile unhuman coworker among them.
| Actor | Role |
|---|---|
 Sergei DesnitskyPirx | Pirx |
 Vladimir IvashovBrown | Brown |
 Aleksandr KaydanovskiyNowak | Nowak |
 Tõnu SaarWeber | Weber |
 Zbigniew LesieńCalder | Calder |
 Bolesław AbartOtis | Otis |
 Ferdynand MatysikUnesco Director | Unesco Director |
 Igor PrzegrodzkiMcCuirre | McCuirre |
 Faime JurnoNot listed | Not listed |
 Zygmunt BielawskiTech Companies Representative | Tech Companies Representative |
 Janusz BylczyńskiJudge | Judge |
| AAdam CieślakNot listed | Not listed |
 Edmund FettingProsecutor | Prosecutor |
 Józef FryźlewiczDefense Attorney | Defense Attorney |
| MMarek IdzińskiCourt Member | Court Member |
 Mieczysław JanowskiMitchell | Mitchell |
| ZZ. JurkowskiNot listed | Not listed |
 Jerzy KaliszewskiAndroid Creator | Android Creator |
 Eugeniusz KujawskiCourt Member | Court Member |
 Ewa LejczakNot listed | Not listed |
| EErwin NowiaszakUnited Atomic Laboratory CEO | United Atomic Laboratory CEO |
 Henryk TalarTom Novak (voice) (uncredited) | Tom Novak (voice) (uncredited) |