The 39 clues. Main series

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.

A clue found in Book 3 sends Amy and Dan jetting off to find out what's behind the fierce rivalry between the Tomas and Ekaterina branches of the Cahill family. Was a clue stolen from the Tomas branch? Where is it now? And, most important, can Amy and Dan get their hands on it before their rivals do?

"Are some secrets better left buried? As Amy and Dan track the next clue to a remote corner of the world, they make shocking discoveries about the source of the Cahills' power and the mystery of their parents' deaths. And as the threat of the mysterious Madrigals grows real, one of the clue-hunters makes the ultimate sacrifice. Amy and Dan have to decide how much they're willing to risk, and what they are fighting for. Can they avenge their parents...

As the race to find the 39 Clues builds to its explosive finish, Amy and Dan must explore an ancient culture and steal a clue guarded by thousands of the world's best-trained soldiers. It's the most dangerous search yet ... and it may mean the end for Amy and Dan.

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,...