What would happen if you discovered that your family was one of the most powerful in human history? What if you were told that the source of the family's power was hidden around the world, in the form of 39 Clues? What if you were given a choice - take a million dollars and walk away...or get the first Clue? If you're Amy and Dan Cahill, you take the Clue - and begin a very dangerous race.

Amy and Dan find themselves in a new global race but this time, everything’s different. Those closest to them might be working for the enemy, and Amy and Dan are forced to ask themselves how far they’re willing to go to save the kidnapped Cahills. How much can you risk when there’s no one to trust?

The Cahill family has a secret. For five hundred years, they have guarded the 39 Clues - thirty-nine ingredients in a serum that transforms whomever takes it into the most powerful person on earth. If the serum got into the wrong hands, the disaster would rock the world. So certain Cahills have always made it their mission to keep the serum safe, buried, locked away. Until now. Thirteen-year-old Dan Cahill and his older sister, Amy, are the latest guardians of the Clues. They think they've done everything right, but a tiny mistake leads to catastrophe.

At only seventeen years old, Ian Kabra is head of the Cahills, the most powerful family in the world. He has presidents on speed dial, generals at his beck and call. Ian knows he's an ideal leader and the only man for the job. There's just one small problem: He's already messed up big time. A Cahill from the past calling himself the Outcast has risen to challenge Ian with an impossible test. The Outcast has re-created four of history's greatest disasters and dared Ian to stop him.

Calling all Cahills! Announcing a 39 Clues Superspecial adventure - the gang is back, and called to investigate one of their own: Sinead Starling.

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.

As the son of Hades, Nico di Angelo has been through so much, from the premature deaths of his mother and sister, to being outed against his will, to losing his friend Jason during the trials of Apollo. But there is a ray of sunshine in his life—literally: his boyfriend, Will Solace, the son of Apollo. Together the two demigods can overcome any obstacle or foe. At least, that's been the case so far . . . Now Nico is being plagued by a voice calling out to him from Tartarus, the lowest part of the Underworld.

After angering his father, Zeus, the god Apollo is cast down from Olympus. Weak and disoriented, he lands in New York City as a regular teenage boy. Now, without his godly powers, the 4,000-year-old deity must learn to survive in the modern world until he can somehow find a way to regain Zeus' favor. But Apollo has many enemies - gods, monsters, and mortals who would love to see the former Olympian permanently destroyed.

Magnus Chase has always been a troubled kid. Since his mother's mysterious death, he's lived alone on the streets of Boston, surviving by his wits, keeping one step ahead of the police and the truant officers. One day, he's tracked down by an uncle he barely knows - a man his mother claimed was dangerous. Uncle Randolph tells him an impossible secret: Magnus is the son of a Norse god. The Viking myths are true. The gods of Asgard are preparing for war. Trolls, giants and worse monsters are stirring for doomsday.

Fiercetooth, a NightWing obsessed with what could have - and should have - been. Deathbringer, desperate to prove himself as the next great NightWing assassin. Six-Claws, a loyal SandWing, who will soon find that loyalty comes with a price. Foeslayer the NightWing, a dragon in love turned kidnapper, and Prince Arctic of the IceWings, a runaway turned captive. In these four short stories, dig deeper into the world of Pyrrhia to discover what really happened.

Ana Dakkar is a freshman at Harding-Pencroft Academy, a five-year high school that graduates the best marine scientists, naval warriors, navigators, and underwater explorers in the world. Ana's parents died while on a scientific expedition two years ago, and the only family's she's got left is her older brother, Dev, also a student at HP. Ana's freshman year culminates with the class' weekend trial at sea, the details of which have been kept secret. She only hopes she has what it'll take to succeed.

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.

Reef and Theo don't know what's happening to them. They'll be going about their days and then suddenly they'll have these strange flashes of memory—but the memories don't belong to them. And at the same time, their own memories are starting to... vanish. For Reef, this is a big problem, because memories are all he has left of his mom. For Theo, it's strange because the new memories give him a freedom he doesn't have with his domineering dad.

When Clementine Kaye, archivist Beecher White's first childhood crush, shows up at the National Archives asking for his help, Beecher tries to impress her by showing her the secret vault where the president of the United States privately reviews classified documents. They accidentally happen upon a priceless artifact - and find themselves suddenly entangled in a web of deception, conspiracy, and murder.

Emerson Knight is introverted and eccentric and has little to no sense of social etiquette. Good thing he's also brilliant, rich, and (some people might say) handsome, or he'd probably be homeless. Riley Moon has just graduated from Harvard Business and Harvard Law. Her aggressive Texas spitfire attitude has helped her land her dream job as a junior analyst with megabank Blane-Grunwald. At least Riley Moon thought it was her dream job, until she is given her first assignment: babysitting Emerson Knight.