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.

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.

The 39 Clues is unstoppable! The bestselling series returns with an adventure spanning four explosive books and a website that places readers right in the action.

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...

Amy and Dan Cahill have their final confrontation with twisted billionaire J. Rutherford Pierce, a man whose power has no limits and is one step away from being elected president.

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

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.

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,...

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.

Bestselling author Jude Watson takes Amy and Dan on a thrill-packed ride for the 4th installment of The 39 Clues series.

Betrayed by their cousins, abandoned by their uncle, and with only the slimmest hint to guide them, fourteen-year old Amy Cahill and her younger brother, Dan, rush off to Egypt on the hunt for 39 Clues that lead to a source of unimaginable power. But when they arrive, Amy and Dan get something completely unexpected - a message...

Unable to return to their normal lives despite the end of the Clue hunt, new Madrigal leaders Amy and Dan anxiously prepare for a retaliatory strike by the Vespers, who kidnap a number of Cahill family members and demand that Amy and Dan steal a famous painting.