Description Junior Spies Kat Varner and Harry Dunn must uncover a rival spy agency's secret plot involving hippos at the zoo in this hi-lo chapter book adventure. The Junior Spies are at it again! This time, Kat and Harry's mission is to uncover a R.A.V.E.N. plot at the zoo. As they investigate, they discover that the zoo?s real hippos have been swapped with inflatable ones. What is R.A.V.E.N. planning with these fake hippos, and can the Junior Spies foil the evil spy agency's plot? Young readers will find out in this hi-lo spy adventure! With a high-interest topic and text written below the targeted grade level, every book in the Junior Spies series supports phonics skills and fosters reading success.