"Grace is the last matriarch of the Cahills, the world's most powerful family. Everyone from Marie Curie to Harry Houdini is related to the Cahills, yet the source of the family's power is lost. 39 Clues hidden around the world will reveal the family's secret, but no one has been able to assemble them. Now the clues race is on, and siblings Amy and Dan must decide what's important: hunting clues or uncovering what really happened to their parents."--...

"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...

When Amy and Dan learn the truth about the Madrigals and Grace Cahill's alternate will, these discoveries lead to the revelation of a secret about their family and a showdown with the man in black who has been following them.

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.

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.

Siblings Amy and Dan must find out who the Vesper mole is in their innermost circle.

With all the clues pointing towards The Outcast recreating the conditions for the Hindenburg disaster, Dan and Amy Cahill split up in order to discover how this can be the case since no one travels by airship anymore.

Dan Cahill and his sister Amy travel from the hottest to the coldest regions of the world in order to stop someone from using their own power against them.

With Amy and Dan still in pursuit of Pierce, Amy does something unthinkable that sends shockwaves through her family.

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.