On his first day as a fourth-grader, Sune is welcomed by an unwanted surprise. A new boy is in his seat, and he's everything Sune wants to be. Not only that, but his name is also Sune - it's the worst possible start to the fourth grade.
For the sake of the family, Vyacheslav Lazarev left the big aviation. The usual routine of Lazarev and his son Kolya is disrupted by a small bear cub, huddled in the cockpit of one of the planes. Little Mansur - as Lazarev and the others called him - having escaped from poachers, becomes attached to Lazarev.