During construction work in a city park three skeletons are found. Forensics say they are young girls who died about ten years ago. Detectives Pafnutiev and Khudoley discover a button with the image of a propeller in the hands of one of the girls and also find a group photo in their archive where one person is wearing an aviator's jacket.

"Vo vremia stroitelnykh rabot v gorodskom parke obnaruzheny tri skeleta. Kriminalisty ustanovili, chto prinadlezhat oni molodym devushkam, tela kotorykh byli pogrebeny let desiat nazad. Delo porucheno operam Pafnutevu i Khudoleiu. Syshchiki nakhodiat arkhivnye materialy o propavshikh posle vypusknogo vechera trekh shkolnitcakh i ponimaiut, chto shansy vyiti na prestupnika ochen maly: proshlo slishkom mnogo vremeni… Sdvinut delo s mertvoi tochki pomogaet sluchai: v ruke pogibshei devushki naidena pugovitca s izobrazheniem propellera. A na arkhivnoi gruppovoi fotografii v formennoi aviatcionnoi kurtke izobrazhen tolko odin chelovekâ€"--From Amazon.com