The Spy Kid Squad is a book series about adventurous, smart 10 year olds, Skylar and her friends, Bella and Emily, who go on secret spy missions together. Each girl has unique talents, but they come together as a team to accomplish amazing missions. The Lost Diamond is the first in the series. In this book, a powerful diamond has been taken by Dark Eye, a notorious villain, who could use it to control the world. Can the Spy Kid Squad outsmart Dark Eye and his darkions to retrieve the diamond or is this mission too dangerous for kids?