Sixth-grader Seryozha Syroezhkin, whose credo is to live for his own pleasure without straining, quickly sags and takes his double - Electronics into circulation: he offers him to go to school instead of himself and even appear at home, convincing him that this is how he will "become a human" (becoming a person was No one can distinguish Electronics from Sergei. The robot has friends. Teachers cannot rejoice at a capable student who suddenly showed unprecedented talents in mathematics, physical education, drawing and even singing. Sergei's parents are also unaware of the substitution and only rejoice at the success of their pseudo-son...