sentences:  The Mystery of the Third Planet
  
  The Mystery of the Third Planet (, "Tayna tretyey planety"), 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.