Henry, Jessie, Benny, and Violet Alden meet Mike Wood and a strange chain of events begins. Mike's house is mysteriously burned down, a man in a blue hat appears, and the Alden's uranium mine is in danger of being sabotaged. The four youngsters must solve the mystery.
When they take their dog, Watch, for obedience training, the Alden children discover that some of the dogs in the class have vanished and decide to try to solve the mystery of their disappearance.
The Boxcar children travel to Maine, take canoes into the wilderness and live in a house exactly like the one on Surprise Island, except the Maine house is brown, not yellow. They untangle the mystery of the two houses.
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.
Henry, Jessie, Benny, and Violet Alden meet Mike Wood and a strange chain of events begins. Mike's house is mysteriously burned down, a man in a blue hat appears, and the Alden's uranium mine is in danger of being sabotaged. The four youngsters must solve the mystery.
