It's summertime, and Henry and Benny are excited about their new jobs in the local department store. When a valuable vase disappears, the manager suspects the boys of causing trouble. They're innocent, but who is responsible for all the suspicious things going on? It's up to Benny to uncover the mystery. . . .

"Schoolhouse Mystery" The Boxcar Children are spending the summer in a tiny, quiet New England fishing village. The little schoolhouse doesn't have a proper teacher, so the Aldens are teaching There's also a very old library where nobody ever goes -- nobody, that is, except for a mysterious stranger. For such a small town, Port Elizabeth has a lot of secrets "Caboose Mystery" When the Aldens spend the summer riding on a train, they get to live in a train car once again -- this time, they're staying in Caboose No. 777. The number is hard to forget, and indeed, the children meet people at each stop who seem to know it well. It turns out Caboose No. 777 has an unusual past -- one that comes with its very own mystery "Houseboat Mystery" The Aldens are spending the summer traveling on a houseboat But someone is watching them -- and the thing that he wants is somewhere on their boat He'll stop at nothing to get it and it's up to the Boxcar Children to figure out why

A double puzzle involves an old friend of Aunt Jane's, romance, and a chase.

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