When Lu and Clancy find a map labeled ?Top Secret? and a note written in code in Aunt Izzy's trunk, the mystery begins. Is Aunt Izzy a spy? The canine sleuths dress up in disguises to follow her. This case proves so full of surprises that the detectives need all their skills and nifty spy stuff to solve it.This Level 2 first reader contains longer stories, varied sentences, increased vocabulary, more difficult visual clues and some repetition.