At the same time that the Alden children's efforts to raise money for a new hospital wing are being sabotaged by nasty tricks, they find their attempts to befriend the new girl Beth frustrated by her strange behavior.
The Alden children visit a family friend at his apple orchard which is rumored to be haunted, but instead of a ghost they find that some of the family's valuable antiques are being stolen.
While helping their grandfather prepare for Greenfield's Winter Festival, the Alden children uncover a mystery surrounding the statue in the town square.
The Boxcar Children are vacationing on an uninhabited South Seas island, but soon suspect that someone else may be there too-- someone who may not want them around!
While canoeing and backpacking near Timberwolf Lake, the Aldens receive strange warnings to stay away from the area and stumble upon clues to a missing cache of stolen coins.
When Lord Cucuface, head of Madeline's school, takes a telescope from the attic during a surprise inspection, its ghostly owner convinces Madeline to help get it back, with help from neighbor Pepito and her fellow orphans.
Henry, Jessie, Violet, and Benny begin to dig into the past of the old boxcar turned playhouse in their back yard and discover clues about why it is being haunted.
"This is an old story. It is about a girl named Otilla who runs away. It is also about a house in the woods, and a skull who lives there, and a secret the skull has, and the night that Otilla finds out what that secret is."--
The Alden children draw upon their resourcefulness to save the neighborhood firehouse from being torn down, while they also face a series of mysterious incidents connected with it.
While the Aldens are visiting a friend of Grandfather's at the beach, Benny finds a long-lost piece of a map to a legendary pirate treasure, a discovery that brings unwanted attention from fortune hunters.