One day, the hapless rogue Gosha Antonov stole the Guarneri violin. But, substituted and robbed by an accomplice, immediately turns out to be the main suspect and also without a violin. The case is entrusted to Vera Barkhatova, a junior investigator in the department of Lieutenant Colonel Artem Guzin. However, after an argument with her boss, she is fired. Meanwhile, Gosha’s workmate, Pavel Petrovich Skorobtsev, nicknamed the Scarab, is found dead.

Gosh realizes that the only way to prove his innocence is to surrender and take the side of the investigation. So the loser thief Gosh and the former investigator Vera, who wants to annoy her former colleagues, decide to launch their own investigation and create a detective agency "Alibi". And this investigation will not be the only one. After all, now they have one "Alibi" for two!