The Boxcar Children, suspicious when someone steals the note they found inside the pages of a "Captain Fantastic" comic book, team up with the superhero's creator to find out who is selling fake copies of the comics.
While visiting a small town in Alabama, the Aldens hear mysterious howls at midnight, leading them to wonder if an old local legend about a ghost dog is true.
When the Aldens visit Yellowstone they discover a map showing the way to an old cabin where gold is supposedly hidden, but they encounter lots of interference in their attempts to hike the trail.
When their grandfather arranges for them to spend two week at Sunny Oaks, the four Alden children enjoy settling into the routines of farm life but become suspicious about a mysterious horse locked in the stables.