The Boxcar children investigate the disappearance of a student's research paper from an observatory and the subsequent disappearance of another student.
At the request of their distant relative Althea, the Boxcar Children arrive at her old Virginia mansion and investigate the mysterious incidents happening there.
The Alden children discover another mystery when the agree to help injured Mr. Yee tend to his plot in the community garden and find out that vegetables are going missing and plots are being vandalized.
When their favorite pizza restaurant almost goes out of business, the Alden children try to help their friends stay open while they find out who is behind all their problems.
