The Mystery of the Secret Message: The Aldens are helping their grandfather organize Greenfield's Winter Festival. When the Boxcar Children get a roll of photos developed, they find a secret message hidden in one of them. They are baffled, and things become even more mysterious when they realize that someone is trying to ruin the Winter Festival by tearing down the ecorations and stealing a local statue! There must be a connection between the message...

"The old abandoned school in Silver City is being fixed up as an art center and the Boxcar Children volunteer to help clean up the place. But the other volunteers are scared by the spooky goings-on in the school--doors lock by themselves, and chalkboard messages appear out of nowhere! Will the Aldens find out the secret of the haunted school?"--

The Alden children have an adventure as they journey along with the Little North Railroad in two cabooses rented for the summer by their grandfather.

The Alden children are thrilled when a famous orchestra comes to their town to perform, and when an original Mozart score turns up missing, they solve the mystery of its disappearance.

The Aldens are excited to meet their favorite celebrity--Walter the Cat, who makes the funniest videos on the Internet! And when this celebrity cat inherits a million dollars from his owner, he becomes even more famous! But someone seems to be angry about the will and is stealing things from Walter's house. Is this cat too famous for his own good?

"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!"--WorldCat.

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

The Boxcar children are helping out at a radio station where strange things are happening.

On a rafting trip in the Pacific Northwest, the Aldens come across the story of a mysterious man who disappeared into the wilderness many years ago. Can you help the Aldens find out where the man went--and what happened to the treasure he took with him? In this interactive, choose-your-path mystery, readers will make decisions that will help the Boxcar Children crack the case during their white-water adventure.

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.