For help, contact private detective N.F. Trubnikov is approached by his friend B.A. Urban. Boris celebrated the New Year with the bride's parents, who live in the Rostov region, and Boris and Lena are going to spend the winter holidays in Dombay, they have already bought vouchers. Returning home to Rostov-on-Don and driving across the bridge over the Bystraya River, they saw their grandmother bleeding. They helped her and took her to the hospital on time. However, the old woman’s husband went missing, and the car that the old people wanted to sell went missing. Urban and Lena are given a written undertaking not to leave. Nikolai Fedorovich begins an investigation to help his friend.