In the detective system of the Russian Empire at the end of the 19th century, a special role was played by thiefs - agents who searched for dangerous criminals for a fee. In a world where passports have no photographs and alibis take months to verify, you can only rely on experience and instinct. And now, after the suspicious death of a theatrical leading lady, detective Pyotr Aleksandrovich Azarevich has four suspects, two actresses, each of whom could become a victim of an invisible killer, very little time and no room for error.