A lovable dog helps his human girl solve a mystery.
What do the letters say?.
The two letters are the same, except for the second word.
What does King know? --Jillian left the letters.
It\'s someone she and Mason both know.
What does Kayla know? --The same person left both letters.
Kayla and Mason both got mysterious letters, written in code.
A lovable dog helps his human girl solve a mystery