In the second part of the adventure duology, ninth-graders Olya, Nastya, Hammer, and Gleb continue their treasure hunt. During summer vacation, they travel to Bulgaria, guided by clues from an antique postcard marked "I am Tajik." Perhaps it is there, in one of the mountain caves, that chests with gold belonging to an extravagant Kaliningrad tycoon are hidden. The local girl Vikhra, who, like Olya, is passionate about postcrossing, offers to help the newly minted treasure hunters, though Hammer finds her excessive friendliness suspicious. It gradually becomes clear that suspicion cannot be cast only on Vikhra’s hidden motives. The protagonists are confident that after traveling the "Dead Man's Labyrinth" in the Kaliningrad region, they are ready for any difficulties. However, the real serious trials await them beyond the threshold of the mysterious "Smuggler's Shelter." Tireless traveler Evgeny Rudashevsky, with unchanging love for historical and travel details, vividly describes southern Bulgaria and concludes the plotlines of "Rathshof Post Station"—the Rhodope Mountains with the town of Madzharovo provide a magnificent backdrop for the series of events in "Smuggler's Shelter." Evgeny Rudashevsky is a finalist for the 2023 National Award in Children's and Youth Literature for contributions to the development of children's literature, a two-time laureate of the All-Russian competition for the best literary work for children and youth "Kniguru," and laureate of the V. P. Krapivin and "Book of the Year" awards. His works are included in the catalog of outstanding children's books of the world "White Ravens" of the Munich International Youth Library and are translated into foreign languages.