It's no longer a game. The body count is rising. Shaken by recent events, Amy and Dan flee to a distant land and trace the footsteps of their most formidable ancestor yet: a military leader of mythic proportions. Yet just as the siblings begin to master the art of ancient warfare, they confront a dangerous enemy that can't be felled with a sword: the truth. With the stakes higher than ever, Amy and Dan uncover something so devastating it changes everything...

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.

Amy and Dan are hot on the trail of the fourth Clue, but their ruthless relatives will stop at nothing to eliminate them from the competition. Their hunt leads them to an ancient city that has been a hotbed of Cahill activity for centuries. The clock is ticking for Amy and Dan.

Amy and Dan Cahill hit the high seas as they follow the trail of some infamous ancestors to track down a long lost treasure. However, the real prize isn't hidden in a chest. It's the discovery of the Madrigals' most dangerous secret and, even more shockingly, the true identity of the mysterious man in black.

Le t the hunt begin. During the reading of their grandmother's will, Dan and Amy Cahill learn that the secrets to their family's power is hidden in the form of 39 Clues around the world. At the reading of their grandmother's will, Dan and Amy Cahill are given the choice of receiving a million dollars or uncovering the 39 clues hidden around the world that will lead to the source of the family's power, but by taking on the clues, they end up in a...

"Amy and Dan were devastated when the Vespers kidnapped seven Cahills around the world, holding them hostage until Amy and Dan delivered an impossible ransom. But at least the hostages were Cahills, members of the world's most powerful family, trained to face all odds. Now the Vespers have gone too far. They've kidnapped Atticus, an innocent 11-year-old boy and Dan's only friend. Now Dan and Amy are in the struggle of their lives. Because if they...

"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....

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 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...

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.