When Quentin Herms is chased from his village into the Quag, a dark forest filled with terrifying beasts and murderous Outliers, Vega uses her skills as a talented decoder to uncover dangerous secrets.

The shadow of the man in black has followed fourteen-year-old Amy Cahill and her younger brother Dan on their worldwide search for 39 Clues that lead to a great power. The man has tried to kill them and he is a Madrigal, as were their parents. And now the man is ready to step out of the darkness for their final confrontation.

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 difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

As they continue their search for the 39 Clues in China, fourteen-year-old Amy is faced with a terrible dilemma when her eleven-year-old brother Dan suddenly disappears--keep on searching for the next Clue or try to find her brother.

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?

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.

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.

When seven members of his family were kidnapped by the Vespers, thirteen-year-old Dan Cahill knew he was in for he fight of his life. He knew he was up against an impossibly powerful enemy. And Dan knew the odds were that some of his family members wouldn't make it. But even as Dan steels himself to accept these facts, the unthinkable happens. The Vespers capture a blameless bystander- Dan's best friend Atticus. With an innocent life on the line,...

When Iranian-American Kamran Smith learns that his big brother, Darius, has been labelled a terrorist, he sets out to piece together the codes and clues that will save his brother's life and his country from a deadly terrorist attack.

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....