In the fifth book of the A to Z Mysteries an early chapter book mystery series featuring strong boy and girl characters Dink keeps getting letters addressed to "D. Duncan." But when he opens them, they all start "Dear Doris" and don't make any sense! Josh and Ruth Rose think someone's playing a trick on Dink. But dink is sure there's more to it than that - especially after Doris Duncan shows up and demands her letters!