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,...

Amy and Dan Cahill are no strangers to impossible tasks. After seven of their relatives were kidnapped, the siblings scoured Europe for the priceless artifacts Vesper One demanded in exchange for the hostages. But then the Cahill kids are given an assignment that pushes them to their breaking point-a journey to a legendary city. Amy and Dan know they can't afford to fail, yet they're running out of options. . . and running out of time.

Publisher Annotation: Mr. Quisling is definitely up to something mysterious, and Emily and James are on high alert. First, there's the coded note he drops at a book event. Then, they uncover a trail of encrypted messages in Mark Twain-penned books hidden through Book Scavenger. What's most suspicious is that each hidden book triggers an arson fire. As the sleuthing friends dig deeper, they discover Mr. Quisling has been hunting a legendary historical...

Commander Gray Pierce and Sigma Force set out to discover a truth tied to the fall of the Roman Empire, to a mystery going back to the birth of Christianity, and to a weapon hidden for centuries that holds the fate of humanity.

"Grace is the last matriarch of the Cahills, the world's most powerful family. Everyone from Marie Curie to Harry Houdini is related to the Cahills, yet the source of the family's 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 the clues race is on, and siblings Amy and Dan must decide what's important: hunting clues or uncovering what really happened to their parents."--...

Commander Gray Perce and the Sigma Force participate in an adventure that races from the Roman Coliseum to the icy peaks of Norway, from the ruins of medieval abbeys to the lost tombs of Celtic kings. The ultimate nightmare is locked within a talisman buried by a dead saint--an ancient artifact known as the Doomsday Key--and a secret that has already claimed the lives of a famed geneticist, a Vatican archaeologist, and a U.S. senator's son.

Gideon Crew--brilliant scientist, master thief, intrepid adventurer--is shocked when his former employer, Eli Glinn, vanishes without a trace, and Glinn's high-tech lab Effective Engineering Solutions shuts down seemingly overnight. Fresh off a diagnosis that gives him only months to live, Crew is contacted by one of his former coworkers at EES, Manuel Garza, who has a bead on one final treasure hinted at in EES's final case, the long-awaited translation...

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.

657 days ago Meg's British father left their home in France to fight the Nazis, leaving some codes in a jar for her to decipher, and Meg and her French mother moved to the Perche, a region in France near Normandy known for its forests; now Meg watches the German soldiers in town, and sometimes carries messages for the French resistance--but suddenly things have gotten much more dangerous: there is a wounded British officer hiding in her grandmother's...