(RUS) «Та́йна тре́тьей плане́ты» — советский полнометражный научно-фантастический мультфильм Романа Качанова, экранизация повести Кира Булычёва «Путешествие Алисы» («Алиса и три капитана») из цикла «Приключения Алисы».

(ENG) The Mystery of the Third Planet, aka The Secret of the Third Planet is a 1981 Soviet traditionally animated feature film directed by Roman Kachanov and produced by the Soyuzmultfilm studio in Moscow. It is based on a children's science fiction novella "Alice's Travel" by Kir Bulychev, from Alisa (Alice) Selezneva book series.
At the end of the 22nd century Alisa Seleznyova, her father Professor Seleznyov and pilot Zeleny go on a space expedition to find rare animals for Moscow Zoo. On the way they seem to encounter a mysterious conspiracy led by Doctor Verhovtsev against legendary Two Captains Kim and Buran. The only clue is a talking bird Govorun that our heroes accidentally took possession of.