Jamila Waheed is staring down a lonely summer in a new neighborhood--until she meets Shirley Bones. Sure, Shirley's a little strange, but both girls need a new plan for the summer, and they might as well become friends.

Then this kid Oliver shows up begging for Shirley's help. His pet gecko has disappeared, and he's sure it was stolen! That's when Jamila discovers Shirley's secret: She's the neighborhood's best kid detective, and she's on the case. When Jamila discovers she's got some detective skills of her own, a crime-solving partnership is born.

The mystery of the missing gecko turns Shirley and Jamila's summer upside down. And when their partnership hits a rough patch, they have to work together to solve the greatest mystery of all: What it means to be a friend.