The positive assessment of the work of young historian Nadezhda Kovrova went to her head. Confident in her infallibility, she makes a mistake.
| Actor | Role |
|---|---|
 Galina KorotkevichNadezhda | Nadezhda |
 Vladimir PetrovMikhail | Mikhail |
 Yuri BublikovYasha | Yasha |
 Anatoliy KuznetsovKrylov Ivan Ivanovich | Krylov Ivan Ivanovich |
 Vladimir TaskinAcademician Alexander Alexandrovich Petrov | Academician Alexander Alexandrovich Petrov |
 Georgy AnchitsSuzdaltsev | Suzdaltsev |
 Lev ShostakZdobnov | Zdobnov |
 Lyudmila PonomarevaKatya | Katya |
 Anatoli Abramovhostel commandant | hostel commandant |
| AAlexandra TrishkoAunt Masha | Aunt Masha |