As the race to find the 39 Clues builds to its explosive finish, Amy and Dan must explore an ancient culture and steal a Clue guarded by thousands of the world's best-trained soldiers. It's the most dangerous Clue search yet ... and it may mean the end for Amy and Dan.

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...

Thirteen-year-old Dan Cahill and his older sister Amy race against time to find an ancient map that has not been seen for half a century and use it to redeem their family members who have been kidnapped by a sinister organization called the Vespers.

A mysterious telegram sends Amy and Dan Cahill off to Russia, where they search for a treasure stolen by the Nazis, the truth about the end of the Romanov dynasty, and information about the death of their parents.

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....

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...

Thirteen-year-old Dan Cahill and his older sister, Amy, thought the search for the thirty-nine clues leading to the source of their family's power was over, but when Cahills are kidnapped by the Vespers, Amy and Dan find themselves with only a few day to fulfill a bizarre ransom request before their friends start dying.

Minutes before she died Grace Cahill changed her will, leaving her descendants an impossible decision: "You have a choice - one million dollars or a clue." Grace is the last matriarch of the Cahills, the world's most powerful family. Everyone from Napoleon to Houdini is related to the Cahills, yet the source of the family 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...

Using their code-breaking skills, four middle-schoolers solve the mystery of the eccentric man who draws stick figures on his second-floor bedroom window.

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