In the second part of the adventurous duology, ninth graders Olya, Nastya, Hammer, and Gleb continue their quest for treasure. During the summer holidays, they head to Bulgaria, guided by clues from an antique postcard «I am Tajik». Perhaps it's there, in one of the mountain caves, that the chests of gold belonging to the extravagant rich man from Kaliningrad are hidden. A local girl, Vihra, who is also passionate about postcard crossing like Olya, offers to help the budding treasure hunters, but Hammer finds her excessive friendliness suspicious.
Gradually, it becomes clear that one can suspect hidden motives not only in Vihra.
The heroes are confident that after their journey through the «labyrinth of the dead» in Kaliningrad region, they are ready for any difficulties.
However, truly serious trials await them beyond the threshold of the mysterious «smuggler's shelter».