Benny wants adventure and finds it as he and the other Alden children help uncover the plan of those who would prevent ballooning from coming to Lloyd's Landing.

While visiting an old mansion, the Aldens investigate the possibility that it may be haunted.

Jessie wants her science fair project to make a difference. So when she gets the chance to test a local creek for pollution, she can't wait to get started. But when things start going wrong with her experiment, Jessie and her siblings don't just have an experiment to investigate, they have a mystery to solve!

The Aldens are excited when a new store called the Game Spot opens up in town, but after a series of robberies at the other stores in the mall, the siblings have a new mystery to solve.

Can the Aldens figure out who's responsible for the bad press before the center gets shut down for good? Henry, Jessie, Violet, and Benny are excited to learn more about raptors when they volunteer at a rehab center for wild birds. But not long after they arrive, a series of strange events makes it seem like someone might be trying to sabotage the center. Who could the culprit be, and why would they want to cause trouble for injured birds?

Henry, Jessie, Violet, and Benny are not expecting a mystery when they offer to show their new neighbors around Greenfield, but when they uncover a series of coded messages hidden in historical documents, they realize they might still have a lot to learnabout their hometown's past.

When the Alden children accompany their grandfather to the Snow Haven Lodge, a series of odd occurrences threaten to disrupt the annual winter games.

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

The Aldens accompany their grandfather to his class reunion and investigate the possibility of a buried Civil War treasure, and of a ghost in the bell tower, at Goldwin University.