Olga's birthday, her loving husband Boris wants to celebrate on a grand scale in a restaurant on the ship and invites many guests. Boris solemnly presents his wife with a very expensive diamond pendant, but the decoration soon disappears under mysterious circumstances. Artyom, Lena, Vadik and, of course, Mukhtar begin an investigation, but Mukhtar suddenly loses track…
 

Lena Brusnikina, coming to work in the morning, impresses everyone with her appearance. On the instructions of the jealous Artyom, Oksana finds out from her friend the reason for the changes. It turns out that Lena met a certain Pavel, and now they have a romantic relationship. On the same days, there is a robbery against the auditor Vinogradov, who works with private construction companies. And, as it turns out, Pavel did not appear in Lena's life by chance…