Lu & Clancy's Secret Codes

An activity-mystery book built around sixteen codes readers must decipher to help two dog detectives, Lu and a basset hound named Clancy, track down Lu's missing sister.

The codes range from familiar backwards writing and number substitution to less common forms: a musical code, a pinprick code, a crossword-style code, and one based on the ancient ogham alphabet, illustrated using broken pieces of spaghetti. Each code comes with a practice message, and the answer key at the back is paired with a set of forensic-science puzzles.

The book is part of Mason's longer-running Lu & Clancy series for Kids Can Press, which continued with titles including The Carnival Caper and Sound Off, pairing mystery-solving with hands-on science and puzzle activities for young readers.