The book opens with a fictional narrative revealing a mystery posed by a that the reader must solve. Following that are the 16 envelopes, each of which contains cryptic clues. The clues will include anagrams, picture- grams, number puzzles, and word plays. Once solved, each letter will reveal one word. Once all 16 letters have been solved, the reader can assemble the 16 words to construct the answer to the mystery.