Plagued by nightmares from their summer in the Brookline asylum, Dan, Abby, and Jordan return to New Hampshire College for a prosective students weekend, only to find themselves caught in a dark and dangerous mystery.

The fourth graders of Makawee Elementary are assigned to do their first real research project. Ginni thinks she will do hers on the female pilot, Amelia Earhart--just like her mom, who was killed flying an airplane. Then strange things start happening at the library that make it seem haunted, and mysterious footprints appear outside the window. Ginni and her friend Frankie have all they can do with the research project and two mysteries.

Someone burns down the home of the school janitor and he dies in the blaze. Everyone in Addamsville, Indiana, points a finger at Zora Novak, despite the fact she has been on the straight and narrow since her father was thrown in jail. Addamsville has a history of tragedy, and thirty years ago a similar string of fires left several townspeople dead. The arsonist was never caught. Teaming up with her cousin Artemis, an annoying self-proclaimed Addamsville...

Best friends Aldo, Pen, and Jasper stumble onto an abandoned orphanage and discover that freeing a houseful of imprisoned ghosts from an angry poltergeist could get them into serious trouble.

After a tragic death at Fairview Public Library, frequent patron Mallory and community service volunteer Spencer discover they are not as alone, or as safe, as they thought.

"Olive discovers an old theater where she'll finally have a chance to shine on stage, but this theater--and its mysterious owner--are hiding dark secrets"--

Shortly after Miles Watley visits the Bell Witch Cave, in Adams, Tennessee, ghostly things start happening.

On the way to spend a summer with her grandmother after the sudden death of her mother, seventeen-year-old Audrey, her older brother Daniel, and their father happen upon the Hotel Ruby, a luxurious place filled with unusual guests and little chance of ever leaving.

When a series of strange ghostly happenings disrupts Seattle Public Library's Halloween party, it's up to Kaz, Claire, and Little John to go underneath the city and investigate.

Kaz are Claire are on the case again—this time, they're looking for Kaz's long-lost uncle! Their search takes them to a bakery and a movie theater. Along the way, they meet another kid ghost detective. Will Kaz and Claire be able to figure out what's going on?