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. The situation is overshadowed by the fact that his chosen one has a fiancé - a real sea captain. But Denis's friends will not leave him in trouble and will make every effort so that Denis can eliminate his competitor and win the heart of nineteen-year-old Natasha.