"Amy and Dan Cahill have been located once again, this time in the company of the notoriously unreliable Alistair Oh. Could they have been foolish enough to make an alliance? Spies report that Amy and Dan seem to be tracking the life of one of the most powerful fighters the world has ever known. If this fearsome warrior was a Cahill, his secrets are sure to be well-guarded . . . and the price to uncover them just might be lethal."--Publisher.

When their beloved aunt--matriarch of the world's most powerful family--dies, orphaned siblings Amy and Dan Cahill compete with less honorable Cahill descendants in a race around the world to find cryptic clues to a mysterious fortune. Includes game cards which the reader may use to play an online version of the treasure hunt.

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.

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....

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?

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,...

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.

Sarah and Aidan begin to decipher a mysterious document that refers to the origins of Peter Pan and are suddenly pursued by a being that can take any form and will stop at nothing to get what it wants from them.

When seven members of their family were kidnapped, thirteen-year-old Dan Cahill and his older sister, Amy, got ready for the fight of their lives. But their enemy, a terrifying group known as the Vespers, remained frustratingly elusive. They stay in the shadows, picking off Cahills one by one. And now the Vespers have landed their most serious blow yet ? A blow that strikes at the very heart of the Cahill family. Because Amy and Dan discover that...