Charlie Thorne is a genius. Charlie Thorne is a thief. Charlie Thorne isn’t old enough to drive. And now, it’s up to her to save the world.... Decades ago, Albert Einstein devised an equation that could benefit all life on earth - or destroy it. Fearing what would happen if the equation fell into the wrong hands, he hid it. But now, a diabolical group known as the Furies are closing in on its location. In desperation, a team of CIA agents drags Charlie into the hunt, needing her brilliance to find it first - even though this means placing her life in grave danger.

Ben Ripley may only be in middle school, but he's already pegged his dream job: CIA or bust. Unfortunately for him, his personality doesn't exactly scream "secret agent". In fact Ben is so awkward, he can barely get to school and back without a mishap. Because of his innate nerdiness, Ben is not surprised when he is recruited for a magnet school with a focus on science - but he's entirely shocked to discover that the school is actually a front for a junior CIA academy.

Sara Martinez is a hacker. She recently broke into the New York City foster care system to expose her foster parents as cheats and lawbreakers. However, instead of being hailed as a hero, Sara finds herself facing years in a juvenile detention facility and banned from using computers for the same stretch of time. Enter Mother, a British spy who not only gets Sara released from jail but also offers her a chance to make a home for herself within a secret MI5 agency. Operating out of a base in Scotland, the City Spies are five kids from various parts of the world.

After an escaped kangaroo starts a fire that burns down his house, Teddy Fitzroy accepts an invitation to go to Malibu with his girlfriend, Summer, and her mother, Kandace. He’s hoping to spend some time relaxing on the beach, but wherever Teddy goes, trouble isn’t far behind. First, a massive dead whale has washed up on the beach—and before anyone can determine what killed it, it explodes. Doc, the head vet from FunJungle, suspects something fishy is going on and ropes Teddy and Summer into helping him investigate.

Like his fellow lunarnauts - otherwise known as Moonies - living on Moon Base Alpha, twelve-year-old Dashiell Gibson is famous the world over for being one of the first humans to live on the moon. And he's bored out of his mind. Kids aren't allowed on the lunar surface, meaning they're trapped inside the tiny moon base with next to nothing to occupy their time - and the only other kid Dash's age spends all his time hooked into virtual reality games.

On a family trip to Paris, Greg Rich's parents disappear. They're not just missing from the city - they're missing from the century. So, Greg does what any other 14-year-old would do: He travels through time to rescue them. Greg soon finds out that his family history is tied to the legendary Three Musketeers. But when he meets them, they're his age, and they'll only live long enough to become true heroes if he can save them.

Teddy Fitzroy's back for another zoo mystery this time it's a koala caper in this action-packed follow-up to Belly Up, which Kirkus Reviews called great fun. School troublemaker Vance Jessup thinks Teddy Fitzroy's home at Fun Jungle, a state-of-the-art zoo and theme park, is the perfect place for a cruel prank. Vance bullies Teddy into his scheme, but the plan goes terribly awry. Teddy sneaks into the koala exhibit to hide out until the chaos dies down.

Twelve-year-old Theodore “Teddy” Roosevelt Fitzroy believes that Henry, the hippopotamus at the brand-new FunJungle, has been murdered. The zoo’s top brass claim the hippo went belly up the natural way, but Teddy and his feisty friend Summer McCraken have other ideas. Could the culprit be FunJungle’s animal-hating head of operations? Or is it FunJungle’s owner - Summer’s dad - a man who is much more concerned about money than animal welfare? The deeper Teddy and Summer dig, the more danger they’re in - because when it comes to hippo homicide, the truth can’t be caged!

Having assumed the identity of a young D’Artagnan, Greg Rich is beginning to get the hang of things in 1615 Paris. But he hasn’t figured out how to get home yet. Or how to defeat the dangerous Michel Dinicoeur, who has made it his mission to destroy Greg, Athos, Aramis, and Porthos. When Dinicoeur escapes the Bastille and flees to Spain, the Musketeers charge after him, only to be ambushed. Someone is anticipating their every move. Could there be a traitor in their midst?

Teddy Fitzroy, his family, and some other FunJungle employees have been invited to visit a bison ranch just outside Yellowstone National Park that FunJungle’s owner, J.J. McCracken, is considering purchasing. But as usual, trouble isn’t far behind. The ranch’s endangered bison have been mysteriously disappearing. Then a massive local grizzly bear named Sasquatch breaks into the house, causing chaos. In the aftermath, Kandace McCracken discovers that her exceptionally expensive sapphire necklace has vanished.