The investigation is being conducted... by the Obolensky brothers! They spend the summer at the dacha, and there are countless crimes there. But Alyoshka and Dimka will find out everything: where the stork is going, and some shiny little things are disappearing into some crow’s nest, and who is robbing the titmice, and why a suspicious squeak is heard from the birdhouse. And strange people begin to hang around the Obolenskys’ dacha, and all of them are somehow connected with a rich mansion on the edge of the village. But Alyoshka and Dimka stand in the way of sinister plans - and now birds, mice and even frogs become their faithful helpers!