Cheburashka has been living with Gena for a year now. Ushatik is growing up, and the friends often have disagreements: Cheburashka begins to show excessive independence and misbehave, and Gena tries to discipline him.
They are invited to Sonya's lavish birthday party, where Ushatik accidentally ruins the celebration. Hoping to avoid another fight, Cheburashka, Sonya, and Grisha secretly escape to the mountains, where incredible landscapes and exciting, yet dangerous, adventures await. Upon discovering the disappearance, the adults team up to bring the children home. They will need to rectify the situation and learn to listen to each other.
