In provincial Sumov, twelve-year-old Kuzma has nothing to do except go to his grandfather, who serves as a doorman at the President Hotel. Unexpectedly, important guests move into the expensive “suite”. The boy overhears their conversation and learns that a military conflict is brewing in a border country, a shift in power in exchange for a pink diamond and the opportunity to help them. Events develop in such a way that the boy becomes acquainted with the presidential service, becomes involved in the investigation of the missing jewel, saves the child and finds his mother. He hopes that someday his parents will want to see their son...