This is a present for the first of September - a building of some company “Kis-kis” is being erected on the site of the school stadium! Everyone is unhappy with this - the school principal, the children, their parents. On the construction site there are mysterious and irreconcilable avengers who are doing their best to harm the vile “Kitty-Kitty”. But all is in vain - the leader of the suspicious company, a certain Koshkind, is invulnerable and omnipotent. Who is he? – the great detective Alyoshka Obolensky is losing patience. And, in order to save the school from this nightmare, he begins an investigation into the cunning activities of the vile Koshkin...