Throughout the hunt for the 39 Clues, Amy and Dan Cahill have uncovered history's greatest mysteries and their family's deadliest secrets. But are they ready to face the truth about the Cahills and the key to their unmatched power? After a whirlwind race that's taken them across five continents, Amy and Dan face the most the difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

12 monkeys: A lone time traveller from the year 2035 must solve a riddle that may save his people ... but it may also take him to the brink of madness. Mercury rising: Art Jefferies, a renegade FBI agent, combats ruthless Federal agents to protect Simon, a nine-year-old autistic boy who has cracked the govrenment's new "unbreakable" code. The jackal: A ruthless assassin has been hired to emiminate someone at the very top of the U.S. govrnment. Constantly...

After twelve-year-old Addison Cooke's uncle unearths ancient Incan secrets in Peru, he is kidnapped by a shadowy organization intent on stealing the treasure unless Addison and his friends can decipher the clues first.

Thirteen-year-old Ruby Redfort is an undercover agent and genius codebreaker.

Crack the code with Carmen Sandiego! In this original story inspired by the Netflix animated series, a special clue-decoding wheel built right into the front cover allows readers to hunt for long-lost pirate's treasure alongside the world's greatest thief.

Cahills are being kidnapped by a shadowy group known only as the Vespers. Now Amy and Dan have only days to fulfill a bizarre ransom request or their captured friends will start dying. Amy and Dan don't know what the Vespers want or how to stop them. Only one thing is clear. The Vespers are playing to win, and if they get their hands on the Clues ... the world will be their next hostage.

Twelve-year-olds Ambrose, Tom, and Frankie are transported to the boys' hometown of Freedom Falls, Ohio, in 1852 when Frankie blows her Romani family's magical trombone, and to return home they'll have to use both Morse code and the ancient form of divination known as the I-ching.

Redemption: A damaged ex-special forces soldier trapped in the criminal underworld is transformed into an avenging angel when an unexpected opportunity allows him to assume another identity. Once believing he was beyond redemption, he now seeks out his own version of justice. Safe: When a second-rate cage fighter, Luke Wright, is tormented by the Russian Mafia and wanders the streets of New York, he witnesses a young Chinese math prodigy, Mei, being...

An escalating race to find the 39 Clues finds Amy and Dan pursuing a Clue guarded by thousands of the world's best-trained soldiers, an effort that separates them in explosively dangerous ways.