The Mystery of the Third Planet / Tayna tretyey planety English Subtitle

Captain Zelyonyy (Green), Professor Seleznyov and his daughter Alisa Selezneva set out from Earth aboard the starship "Pegas" (Pegasus), seeking out new animal species for the Moscow Zoo. On the advice of the archaeologist Gromozeka, they turn to Doctor Verkhovtsev, the director of the Museum of Two Captains, for help. But the doctor behaves suspiciously: he refuses to show them the Captains' diaries and starts spying on the expedition. On the planet Bluk they make some valuable purchases, among them a Chatterer — the bird belonging to the missing captain Kim. A suspicious fat man, Merry Fellow Oo, tries to steal a bird. Having listened to the speech of the Chatterer, the crew of "Pegas" heads for the Jellyfish system. On the road, the heroes rescue robots of the planet Shelezyaka from diamond dust, mixed into machine oil.

On the third planet of the Jellyfish system Alisa finds "mirrors" — the flowers which are memorable and displaying everything that occurred before them. By means of mirrors the heroes find out that on the planet there are Verkhovtsev and the Merry Fellow. In attempt to fly in a safe place of "Pegas" falls in a trap. Seleznyov and Green are captured by pirates, Alisa manages to run away.

On the planet the captain Buran, and with him — the real Verkhovtsev lands. Alisa asks them for help. Meanwhile, the Merry Fellow threatening to murder the captives, demands from captain Kim locked in the ship, a formula of absolute fuel. Buran's invasion rescues the heroes. The double Verkhovtsev, Glot, is exposed. The Merry Fellow in attempt to escape falls into the clutches a bird of prey, Krok. The captains and researchers return home.