The Aldens become involved in a community theater production of "The Wizard of Oz," which is systematically and mysteriously being sabotaged.

When the Aldens go to the Pickering Natural History Museum to assist with the opening of a dinosaur exhibit, their work is hampered by a series of mysterious happenings.

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 go to summer camp, where they suspect that someone is cheating during the Camp Olympics. One warm night four children stood in front of a bakery. No one knew them no one knew where they had come from. Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they're spending a week at Camp Seagull on beautiful Claw Island. When they arrive at Camp Seagull, the Alden children...

Henry, Jessie, Violet, and Benny are actors in a live mystery show being broadcast on an old-fashioned AM radio station. But that's not the only mystery the Boxcar children are part of—it's starting to look like the radio station is haunted!

The Aldens try to help a visiting Russian gymnast who is surrounded by mysterious people and events and who seems to have a secret.

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 families' valuable antiques are being stolen.

While on bicycle trip to their aunt's farm, the four Aldens help solve a mystery.

The Alden children plan to ride in their boxcar at the Greenfield Founders' Day Parade, but the newly refurbished boxcar is stolen a couple of days before the big event.

While exploring the caves around Dragon's Mouth Cavern, a series of unusual and somewhat frightening events convinces the Alden children that someone does not want them around.