Polina has a plasticine country called Lisofange. There lives a girl named Glasha, invented by Polina, who looks like her. Glasha knows how to control the Flying Apartment and fly over the waves on it. - Polina, you are ten years old! “I demand to get rid of the plasticine,” says my mother. And the plasticine country ends up under the bed, and the sun disappears over Lisofange. Glasha goes in search of him and ends up in the attic of an abandoned house. The house where Polina used to live and, together with her dad, painted waves on the door of the room. Now the door is lying in the attic, and through it Glasha goes out into Polina’s world, where she meets Kirill. The boy mistakes the grimy girl for a street child. Imagine his surprise when the next day a new girl comes to their class, exactly like Glasha, only her name is Polina, and she swears that she does not have a twin. What happens when Will Polina meet herself from an imaginary world? And where did Kent come from on the swimming beetle, which attacked Lysofange and bombarded him with mad cucumbers?