Nearly two years ago, Meg Kenyon's father left their home in France to fight for the allies in World War II. Recently, Meg heard he had been taken prisoner by the Nazis. All Meg has left of him now are the codes he placed in a jar for her to decipher, an affectionate game the two of them once shared. But even those are running low. But the codes are running low, and soon there'll be nothing left of Papa for Meg to hold on to at all. Suddenly, an impossible...

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....

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.

A million dollars, or a clue? Police report a break-in at an elite hotel, and the suspects sound suspiciously like Amy and Dan. There's a car and speedboat chase and an angry mob! When there's a clue on the line, anything can happen.

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 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.

Thirteen-year-old Dan Cahill and his older sister, Amy, are the latest guardians of the Clues -- thirty-nine ingredients in a serum that transforms whomever takes it into the most powerful person on earth. They think they've done everything right, but a tiny mistake leads to catastrophe. The serum is missing and Dan and Amy have to get it back and stop who stole it ... before it's game over.

Fourteen-year-old Amy Cahill and her younger brother Dan thought they could return to their regular lives when they found the 39 clues. But the Vespers, powerful enemies, will stop at nothing to get the clues. And with the Vespers rising, the world is in jeopardy.

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,...

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.