King & Kayla are back on the case in this laugh-out-loud mystery from the Theodor Seuss Geisel Honor Award-winning series. King and Kayla receive a mysterious letter written in code. Mason received an almost identical letter. How can they crack the code? Kayla notices that there aren't any vowels in most of the words; you can't write words without vowels. When she compares her letter to Mason's, only one word is different. Sensitive King notices that the letter smells like Jillian. Why would Jillian write them letters in code? With simple, straightforward language and great verbal and visual humor, the King & Kayla series is perfect for newly independent readers. King and Kayla model excellent problem-solving skills, including working as a team, gathering facts, making lists, and evaluating evidence.