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.

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...

Akiko, Mae, and Josie, also called the Infinity Trinity, spring into action after learning that a spy is betraying secrets to the Japanese military--and that Akiko's mother may be involved.--

"Cruz and his fellow recruits tackle challenging missions to dispense life-saving medication to gorillas, thwart pangolin poachers, and capture images of the last known cheetahs in Namibia--all the while discovering that protecting the world's threatened species is a dangerous business. Things turn deadly for Lani, Sailor, Emmett, and Cruz as they search for the fourth piece of Cruz's mom's cipher. Cruz knows it's not going to be easy, but will an...

Amy and Dan cross the oceans on the trail of a famous aviator, but they find more than they're looking for. Their enemies are becoming more vicious, and the truths they discover more crushing than ever.

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,...