Moscow 1950s, June. City residents, having loaded all their scrub from mattresses to pots, into commuter trains, go to dachas and villages. Among them is the family of the boy Denis Korablev. Denis's parents don't really want to continue the tradition of renting a house for three summer months in the countryside, but Denis's grandmother is convinced that fresh country air is extremely useful for all of them. Life in the village is in full swing. Denis's dad rides a bike, Denis's mom walks around the village in a white sundress, Denis's grandmother makes strawberry jam, which is a lot this year. Denis has fun in the village - he joins a local gang of boys, makes friends with a girl Lena, goes to the boat station and plays a lot of mischief. One day, the worst thing for every boy happens to Denis - he falls in love.

A boy nicknamed Uncle Fyodor loved animals very much, but his parents didn't want to hear anything about having a pet in their apartment. So Uncle Fyodor had to move to the village of Prostokvashino with his new friends — the cat Matroskin and the faithful dog Sharik.

The brownie escapes from the captivity of Baba Yaga in her magical world, and ends up in the apartment of the girl Natasha and her parents. Kuzya needs to find his magic chest that grants wishes. Both Natasha and the local grumpy brownie Nafanya help him in this. It turns out that Kuzya himself gave the chest to Andrey, Natasha's dad, many years ago. It would seem that the goal is already close, but in search of both Kuzya and the chest, Baba Yaga entered our world, and she has her own insidious plans.

Sequel to feature film adaptation of "Prostokvashino" by K.B.A.