A million dollars, or a clue? Police report a break-in at an elite hotel, and the suspects sound suspiciously like Amy and Dan. There's a car and speedboat chase and an angry mob! When there's a clue on the line, anything can happen.

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Four presidents of the United States have been assassinated—in 1865, 1881, 1901, and 1963—each murder seemingly unrelated. But what if those presidents were all killed for the shocking same reason: a clause contained in the United States Constitution? This is the question faced by former Justice Department operative Cotton Malone. When President Danny Daniels is nearly killed in the heart...

Amy and Dan, following a clue found in Book 3, set out to uncover details about the origins of the rivalry between the Tomas and Ekaterina branches of their family, not realizing they are headed right into the hands of the enemy.

"Forty years ago, Steven Smith found a copy of a famous children's book by disgraced author Edith Twyford, its margins full of strange markings and annotations. Severely dyslexic and wanting to know more, he took it to his remedial English teacher Miss Iles, not realising the chain of events that he was setting in motion. Miss Iles became convinced that the book was the key to solving a puzzle, and that a message in secret code ran through all Twyford's...

Throughout the hunt for the 39 Clues, Amy and Dan have encountered some of the darkest aspects of history... and had to deal with the role their family played. But are they ready for the truth? In this thrilling ninth installment, Amy and Dan hit the high seas as they follow the trail of some infamous ancestors to track down a long lost treasure. However, the real prize isn't hidden in a chest. It's the discovery of the Madrigals' most dangerous secret...

Eleven-year-old Fish, seeking a way to help his family financially, becomes a reluctant cabin boy on a pirate ship, where he soon makes friends--and enemies--and is asked to help decipher clues that might lead to a legendary treasure.

Amy and Dan Cahill have been located once again, this time in the company of the notoriously unreliable Alistair. Spies report that Amy and Dan seem to be tracking the life of one of the most powerful fighters the world has ever known. If this fearsome warrior was a Cahill, his secrets are sure to be well-guarded.

"Hailey Gordon is looking to make some fast cash to help pay her tuition when she's caught counting cards at the Encore casino in Boston. She grabs her winnings and makes her escape. With guards closing in, she dives into an unlocked room to hide...only to find a dead body. Recently released from prison, Nick Patterson hasn't felt hope in a long time, but the job he "inherited" in prison promises to change that. He enters hotel room 633 to find that...

Akiko, Mae, and Josie, also called the Infinity Trinity, spring into action after learning that a spy is betraying secrets to the Japanese military--and that Akiko's mother may be involved.--