The Legend of the Scythian Gold.

The plot centers on an investigation conducted by the curious and resourceful Petya, despite the entreaties of his friends, family, and local law enforcement agencies, and throughout the entire journey he is "assisted" by his younger brothers, Sasha and Kostya. After a series of failures and setbacks, Petya still does not give up, collects all the evidence together, and learns the truth about who is to blame for the disappearance of the artifacts and helps return these exhibits to the museum.