1818. Odessa, which has been granted the right to free port, is waiting for the arrival of Emperor Alexander I. Then the question will be decided who will equip the customs border, and this promises big money. And then there is an unobtrusive murder of a fishmonger at first. Suddenly it turns out that he is of a difficult origin. And the murder of a nobleman, and even on the eve of the visit of the monarch, is serious for the Russian Empire! The police officer Afanasy Drymov is solving the crime. But at the request of the city authorities, the French citizen Nathan Gorlis, who arrived in Odessa a year ago with the recommendation of Duke de Richelieu, and his friend Cossack Stepan Kochubey. And they have a lot of work ...