Riddle of the Silver Walking Stick - Kid Detectives, #3

Rumour had it Anton's deceased Grandfather owned rare and valuable Bulgarian stamps. Accidently Anton finds a booklet on rare stamps containing a code - hidden in his Grandfathers Silver Walking stick. A set of rare and valuable Bulgarian stamps has been circled in red ink. Julie, Jason and Luke are recruited to help Anton solve the mystery. Did his Grandfather circle the stamps? Did he own those stamps? Will the code reveal the whereabouts of the stamps? Plenty of work for the Kid Detectives.
It does not take the team long to realize they have competition in the search for the stamps. An unknown person or persons is determined to find the stamps before the Kids do - and will resort to shady tactics to gain the prize. With the value of the stamps at $30, 000, motivation is high on both sides to be the first to lay hands on the stamps.