Repnin, a business traveler, arrived in Moscow to ship the equipment and immediately fly to Zausolye, where an expedition was waiting for him. But in the Moscow hustle, Repnin loses all the money that Vadik, Yura and Tosha find. The children got into the victim's position and decided to find him. The key to the search was the trotter test program, in which the money was wrapped. The road to the racetrack turned out to be long and interesting.