When her former best friend gets popular and leaves her behind, sixth-grader Ruth prefers to be alone, studying for the school spelling bee, until she finds a riddle in an old book.

"Former beauty queen and fledgling private investigator Madeline Maclin, has married her best friend, Jerry Fairweather, and settled into his old house in the small town of Celosia, North Carolina...And now Madeline is involved in the mysterious death of Amelia Lever, an unpopular teacher at Celosia Elementary School...And then there's Maddy's latest case. Nathan Fenton has hired her to help solve a riddle left to him by his Uncle Elijah, a man who...

As the new Keepers of the School, sixth-graders Ben and Jill must decipher a handful of clues written as maritime riddles to save their school from demolition by a greedy company.

In 1930 Vermont, Jane Hubbell Kinneson, the last resident of a remote mountain on the U.S.-Canadian border that is threatened by a proposed new highway, confronts a mysterious pilot searching for a cache of stolen gold who crashes his plane on her mountain.

"Three years ago, Detective Saga Bauer received an ominous postcard describing a gun and nine white bullets--one of which was intended for her partner, Detective Joona Linna. The sender alleged that Saga was the only person who could save him. But as time passed, the threat faded. Until now. A sack with a decomposing body has been found hanging from a tree in the forest. A milky white bullet casing turns up at the scene. When the body count begins...

"Maerad's powers grow stronger by the day, but she and her mentor, Cadvan, are hunted by both the Light and the Dark, and their world threatens to erupt into chaos. Their quest to unravel the Riddle of the Treesong leads Maerad over terrifying seas and glacial wilderness, into the grasp of the seductive Winterking and the prison of his icy realm"--Publisher's description.

Flying horses from the Royal Guard arrive in Crystal Cove to deliver a message for Sasha, but in order to open it she must first solve a riddle, which requires her to find the petals of rare and different-colored flowers.

Ten-year-old Flavia and her friends encounter the Roman admiral Pliny before making a journey to her uncle's farm near Mt. Vesuvius, where they try to solve a riddle, reunite a family, and get out of the path of a natural disaster.

When his class wins a free trip to the circus, Goofball gathers clues to track down the winning number his teacher must produce.