To crack a secret code, Mac follows the clues to France and Japan where he must use his gaming skills and defeat his enemy, the KGB Man.

"Amy and Dan were devastated when the Vespers kidnapped seven Cahills around the world, holding them hostage until Amy and Dan delivered an impossible ransom. But at least the hostages were Cahills, members of the world's most powerful family, trained to face all odds. Now the Vespers have gone too far. They've kidnapped Atticus, an innocent 11-year-old boy and Dan's only friend. Now Dan and Amy are in the struggle of their lives. Because if they...

Amy and Dan must find the Outcast before he causes a nuclear meltdown.

After being taught in a boarding school run by whites that Navajo is a useless language, Ned Begay and other Navajo men are recruited by the Marines to become Code Talkers, sending messages during World War II in their native tongue.

Could Amy and Dan's biggest enemy be . . . a friend? Book 6 in the bestselling The 39 Clues series challenges everything you thought you knew about the Clue race. Fourteen-year-old Amy Cahill and her younger brother, Dan, head to the Land Down Under to discover what their own mother and father knew about the hunt for the 39 Clues. But following in their parents' footsteps brings up lost memories for Amy so awful that she can't share them . . . even...

When a mysterious letter written in code arrives at King's house for his human, Kayla, he follows the trail of the person who left it.

Scholar Jules Addison and scavenger Amelia Radcliffe join forces to unravel secrets of a long-extinct civilization, only to discover something that could spell the end of the human race.

When Iranian-American Kamran Smith learns that his big brother, Darius, has been labeled 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.

The heat is on as someone seems to be melting the polar ice cap. Special Agent EJ12 needs to crack the codes and keep her cool to put the evildoer's plans back on ice. That's the easy art. As EJ12, Emma Jacks can do anything. So why can't she handle the school Ice Queen of Mean Nema? Perhaps she can after all...