When Cammie Morgan visits her roommate Macey in Boston, she thinks she's in for an exciting end to her summer. But when you go to the world's best school (for spies), "exciting" and "deadly" are never far apart. The girls suddenly find themselves trapped in a kidnapper's plot, with only their espionage skills to save them.

DJ wants it all: the car, the girl and the truth about his grandfather. After jetting across the Atlantic, DJ follows a series of obscure clues and symbols that lead him deep into the world of British espionage, complete with guns, double agents and a vintage E-type Jag.

After her spy notebook of secrets goes missing and she receives a ransom note, Kelsie tries to solve the mystery on her own but soon realizes she needs everyone in the Curious Cat Spy Club to rescue the notebook, help a homesick 130-year-old Aldabra tortoise, and unmask a thief.

Twelve-year-old Nettie's sheltered and privileged life changes after her beloved tutor mysteriously disappears and Nettie, aided by the son of a household employee, begins to learn the truth about her father, whose wealth began with trafficking in illegal aliens.