A Clue found in Book 3 sends Amy and Dan jetting off to find out just 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?

Amy and Dan cross the oceans on the trail of a famous aviator, but they find more than they're looking for. Their enemies are becoming more vicious, and the truths they discover more crushing than ever.

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.

The fourth book in the CAHILLS VS. VESPERS series, the follow up to the worldwide bestseller THE 39 CLUES.

After pulling some spectacular heists, Amy and Dan have become two of Interpol's most wanted criminals. So when Vesper One orders them to steal the world's largest diamond, they know they're facing life in prison . . . or worse. But with the Cahill hostages still in peril, Amy and Dan have no choice but to launch a mission that leads them...

The Outcast recreates the conditions for the Titanic disaster and gives Dan and Amy Cahill just days to stop the shipwreck from taking place.

Amy and Dan are shocked to learn that Outcast, a violent renegade who is threatening the lives of innocent people, may be a Cahill family member who is determined to exact revenge.

The Cahills are the world's most powerful family, but their strength is being tested. A sinister man calling himself The Outcast has targeted the family and set them an impossible test. He's recreating four of history's worst disasters and challenging the young Cahills to find and stop the tragedies before it's too late. Now, with one disaster behind them, siblings Dan and Amy Cahill and their friends have just days to discover what the Outcast's...

It started with a kidnapping. A shadowy organization known only as the Vespers snatched seven members of the Cahill family and demanded a series of bizarre ransoms from around the world. Thirteen-year-old Dan Cahill and his older sister Amy began a global treasure hunt, determined to bring back whatever Vesper One needed, so long as it kept the hostages safe. But when they deliver the last ransom, Amy and Dan discover Vesper One's terrifying endgame....

After seven members of their family are kidnapped by an organization called the Vespers, Dan and Amy Cahill must race against time to track down an ancient map to pay as ransom to bring the hostages home.

FORMAT: UnabridgedNARRATOR: David PittuThe 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

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