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 strange telegram lures fourteen-year-old Amy Cahill and her younger brother, Dan, deep into Russia and away from the only trustworthy adult they know. Signed with the initials NRR, the telegram launches a race to uncover a treasure stolen by the Nazis and the truth behind the murder of the last Russian royal family. All too soon, the treasure hunt starts to smell like a Lucian trap. But the bait might just be irresistible--what will Amy and Dan...

When Amy and Dan Cahill's quest to find the million dollars takes them to Japan, they must decide whether or not to enter into an alliance with their uncle, Alastair Oh, whose motives for helping them are extremely questionable.

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,...

When Amy and Dan Cahill trace the footsteps of a formidable military leader from the Cahill bloodline, they uncover a devastating secret about the family that changes everything.

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.

Fourteen-year-old Amy Cahill and her younger brother Dan thought they could return to their regular lives when they found the 39 clues. But the Vespers, powerful enemies, will stop at nothing to get the clues. And with the Vespers rising, the world is in jeopardy.

Defend the Clues

Fourteen-year-old Amy Cahill and her younger brother, Dan, thought they could return to their regular lives when they found the 39 Clues that safeguard their family's great power. But they were wrong. Powerful enemies—the Vespers—have been waiting in the shadows. And they'll stop at nothing to grab the Clues. Four powerhouse authors unite to expose the 500-year-old secret struggle between the Cahills and the Vespers. The

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Chronicles the first Vesper attack on Jan van Eyck's altarpiece at Ghent in the 1600s, then jumps to WWII and young Grace Cahill's desperate bid to save the masterwork from the Nazis.

Returned by a surprising twist to their first mission on U.S. soil since the beginning of the Clue hunt, Amy and Dan discover evidence of a mole in their organization who proves to be one of their closest confidantes and who reveals, even more disturbingly, the true agenda of the Vespers.