In the city, an emergency—at the school garden—someone has strangled a senior high school student with a gold chain. Private detective Tatyana Ivanova, taking the case at the parents’ request, is convinced: the classmates know a lot, but stubbornly keep silent—apparently each of them has something to hide. The sleuth, with great difficulty coaxing the teenagers into frankness, learns about the boy’s business relationship with an adult neighbor from the stairwell. Tatyana decides to visit this man, but finds only his dead, mutilated body…