Danny Caulfield's quiet Christmas break from Wilsons Academy, the school for spies, is shattered by gunshots and a heartrending discovery about his parents, and he is called back to Wilsons to prepare to go undercover to protect the Treaty Stone that keeps peace between the Upper and Lower Worlds.

Kidnapped on his way to boarding school, Danny Caulfield, who has one blue eye and one brown eye, ends up at a mysterious academy of spies, where he is to be trained in the art of espionage in an effort to keep the Upper and Lower worlds from colliding.

When Lady Lilah disguises herself to sneak out of the castle she discovers that the country is on the verge of revolution and her brother is behind it, and Lilah and her friends decide to help by becoming spies.

Elf historian Brangwain Spurge is sent to goblin country to deliver a peace offering to their dark lord and spy on the goblin kingdom, but he and his goblin host commit a series of blunders that might bring their nations to war.

As almost thirteen-year-old Ben, a student at the CIA's academy for future intelligence agents, prepares to go to spy summer camp, he receives a death threat from the evil organization SPYDER.

Frank and Joe, the Hardy boys, solve a mystery involving a magician, American secret agents, and international spy ring, and a Scottish castle.

When a former member of NERDS turns into a villainous cheerleader, Matilda "Wheezer" Choi and the rest of the NERDS must infiltrate the cheerleader squad and save the world from a machine that wreaks havoc by entering other dimensions.

Everywhere that Christopher Lane turns, he sees the face of the boy he killed. There is no escape from the guilt, not even on his return to Myers Holt, the secret London academy where he and five others are being trained to use their mental powers, their Ability. But now that the threat of Dulcia Genever has been dealt with, his friends are too busy working for the police, entering the minds of some of the country's most dangerous criminals, to sympathize....

"When Quest (Q) and his stepsister Angela head to Texas for their parents' concert, they discover traces of the terrorist group Ghost Cell in the Lone Star state"-Provided by publisher.

In 1918, caring for her family's homing pigeons while her father is away fighting in World War I, twelve-year-old Pam comes to suspect that a mysterious stranger in her small North Carolina town is a German spy.