"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 with Dan. Haunted by the ghosts of their past, chased by deadly competitors, Dan and Amy can't see who is an enemy and who is a friend. Their blindness leads to a terrible...

Unexpected media attention in their Harlem neighborhood bring Shelby Holmes, nine, and John Watson, eleven, a new case that sends them undercover as figure skaters.

Twelve-year-olds Ambrose, Tom, and Frankie are transported to the boys' hometown of Freedom Falls, Ohio, in 1852 when Frankie blows her Romani family's magical trombone, and to return home they'll have to use both Morse code and the ancient form of divination known as the I-ching.

Fifteen-year-old Matt and his new friend Robin search the globe to retrieve an ancient code--rumored to have brought down the ancient civilization of Atlantis--from the hands of a madman who is bent on destroying the modern world.

When Bertie the badger visits his grandfather at a retirement home for magicians, he learns that his grandfather's rabbit, Enigma, has disappeared along with everyone's magical things, and the reader is invited to help break a code to find the items hidden throughout the book. Includes a built-in decoder.

Liz the Whiz and her younger brother use codes, a chart, and a map of the backyard that matches a clock face to solve Zack's mystery. Includes a section with related activities.

Second-grader Sam Graham wants a cell phone to do research and share information but when his parents say no, he devises a new plan that starts a fad at school.

Rocket, Nuri, and Screech find themselves in 1933 Paris, where a rare and mysterious painting has been stolen, so the young adventures set out on the trail of the stolen artistic treasure and its secrets.

Geronimo Stilton and his sister Thea search for a secret map hidden beneath a famous painting and soon uncover some amazing clues.

"Chris Kingsolver has always been especially close to his aunt. He's heartbroken when she dies in a car accident--and shocked to get a coded letter in the mail after her death. Elsie left Chris clues to the location of a lost treasure ship as an inheritance--if he, his cousin Carrie, and their new friend Maddison can find it. But that might be difficult, what with the mysterious people stalking them, and the strange behavior of the new archivist....