The famous detective duo of Leonov—Makeev is back at the center of events. On his wife’s birthday, Lev Gurov receives an unusual gift—a certificate for a flight on a commercial airplane. But after landing, the event is overshadowed: the pilot is murdered. Gurov manages to hear from the dying man only one word—«Isaev». The next day, an airbase becomes the site of a fire where the second pilot dies, and the operatives discover a large batch of counterfeit dollars in one of the planes. Gurov and Kryachko understand that these events are connected and try to figure out who Isaev is. Answers to these questions require them to return to the past in order to unravel a series of mysterious incidents. Nikolai Leonov, a former MUR investigator, knew perfectly well how to solve complex cases—his books are always full of intrigue and unexpected turns. Colonel Lev Gurov, the main character of his works, is a high-level detective with not only professional skills, but also many positive personal traits. He earns respect from friends, fear from enemies, and sympathy from women—making him a true hero of domestic literature. For forty years, the novels about Lev Gurov have remained popular among detective-genre fans. The «Black Cat» series became a classic, and more than 200 books have been published in huge print runs.