A little girl named Katherine saved one boy's life during the bombing in Leningrad while under the Siege in WWII. The boy cannot speak yet. So she gave him a name Seryozha and provided him with food and care. She was later adopted by the boy's father, who recognized his son.
| Actor | Role |
|---|---|
| TTatyana SoldatenkovaKatya | Katya |
| KKonstantin KornakovSeryozha | Seryozha |
 Nikolai TimofeyevNot listed | Not listed |
 Vera Kuznetsovaтётя Таня | тётя Таня |
 Liliya GurovaNot listed | Not listed |
 Vsevolod KuznetsovNot listed | Not listed |
 Yevgeni GrigoryevIvan Lukich | Ivan Lukich |
 Fedor FedorovskiNot listed | Not listed |
 Zhanna SukhopolskayaЖеня | Женя |
 Stanislav SokolovВолодя | Володя |
 Maya Blinovaмедсестра | медсестра |
| NNikolay Kuzminпечник Трофимов | печник Трофимов |
| VVera Lipstokсоседка-пессимистка | соседка-пессимистка |
 Lyubov Malinovskayaврач | врач |
 Arkadi Trusovшофёр | шофёр |
 Tamara TimofeevaАнна Васильевна | Анна Васильевна |
 Fyodor Nikitinпрофессор, в титрах не указан | профессор, в титрах не указан |
 Pavel Shpringfeldредактор газеты | редактор газеты |
 Lyubov Virolainenвнучка, в титрах не указана | внучка, в титрах не указана |
| LLyudmila Chupiroпродавщица | продавщица |
 Vladimir GreminNot listed | Not listed |