About the book: year / Some people are simply lucky to have adventures! Ivan and Margo discovered that for some reason the door of Margo’s neighbors, the Smirnovs, was open. The guys went inside to find out what was going on. And then someone locked the apartment from the outside! The friends climbed out through the balcony, got the keys and again explored the mysterious place. Margot thought that the neighbors’ former tenant could have broken into the apartment. And the guys put him under surveillance…