"An enigmatic message leads the Code Busters on a treasure hunt on creepy Alcatraz Island, where they must use their problem-solving skills to unravel the mystery"--

Marigold concocts a mystery that finally gets her and her friends into the boys' private eye club.

When a rare coin and a strange code are uncovered in McKenna School, Malcolm and the other classroom pets of the Midnight Academy take on their most challenging assignment yet and, through their investigations, they just might save the school from closing.

"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...

It was only a few weeks ago that the Biedermann twins, Tess and Theo, along with their friend Jaime Cruz, followed the secrets of the Morningstarrs' cipher further than anyone had in its century-and-a-half history -- and destroyed their beloved home in the process. But the Old York Cipher still isn't solved. The demolition of 354 W. 73rd Street only revealed the next clue in the greatest mystery of the modern world, and if Tess, Theo, and Jaime want...

Told in multiple voices, fifteen-year-old Jamaican Louisa Adair uncovers an Enigma machine in the small Scottish village where she cares for an elderly German woman, and helps solve a puzzle that could turn the tide of World War II. A German soldier risks his life to drop off the sought-after Enigma Machine to British Intelligence, hiding it in a pub in a small town in northeast Scotland. Louisa Adair, a teen girl hired to look after the pub owner's...