While trying out the spy glasses, spy hat, and other items in their new spy kit, seven-year-old Henry and his dog Mudge make a new friend and form a spy club.

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.

The solutions to 10 mysteries solved by Leroy "Encyclopedia" Brown are given in a separate section, challenging the reader to match wits with the 10-year-old mastermind of Idaville's war on crime.

When Didi Dodo and her friends hear that the queen was kidnapped by a human, they pose as a family while searching for her at a new, human-themed amusement park.

Aly fails to foresee the dangers that await as she uses her magic to safeguard Dova and her younger siblings, despite knowing that her thirteen-year-old charge might be queen of the Copper Isles when the colonial rulers are defeated.

In her alternate England of 1851, while taking her friend Sidheag by train to her werewolf pack in Scotland, fifteen-year-old Sophronia uncovers a plot that threatens to dissolve all of London into chaos and must decide where her loyalties lie once and for all.

Reluctant teenage-spy Alex Rider, on a routine mission at the Wimbledon tennis championships, gets caught up in Chinese gangs, illegal nuclear weapons, and the suspect plans of his Russian host, General Sarov.

"Meet Winter Young, rookie backup dancer turned global pop phenomenon. His star power has smashed records, selling out stadiums from LA to London. Now he's bringing his swoonworthy assets to a whole new arena...Infamous criminal tycoon Eli Morrison has just one weakness--his daughter, Penelope. And Penelope has just one wish for her nineteenth birthday--a private concert with Winter Young. When the covert ops organization Panacea Group approaches...

"Sure, Jackson and Quigley might officially be too young to join the FBI, but they aren't going to let that stop them! They just need to come up with the right plan to prove that they are worthy. But when one of Q's inventions goes dangerously wrong, Jackson suddenly finds himself dropped right in the middle of an FBI stakeout. There's fishy business afoot at the city's aquarium; rare fish are vanishing and not even the FBI can work out what's going...

When Lulu's parents go on vacation, the formidable Ms. Sonia Sofia Solinsky comes to babysit and Lulu behaves as badly as possible to get her to leave until Ms. Solinsky reveals her secret.