Turning his hand to a bit of 'serious business', Goshka, a swindler and small-time crook, steals a priceless violin only to have it stolen from him by another thief a few days later. Vera, the associate investigator working in the Prosecutor's Office under Colonel Guzin, is assigned to the case, however, she is fired almost immediately after an argument with her boss. Although Gosha no longer has the violin, he is still the main suspect and, realizing he must come clean, he goes to Vera's flat to give himself up and to offer his help with the investigation. A delightful friendship and collaboration begins between the robbed thief and the former investigator, hell-bent on avenging herself on her former boss. The pair go on to handle many other cases - some dangerous and some downright hilarious but all with astonishingly successful results.