Summer vacation on an almost private island gives the Aldens a challenge. Henry, Jessie, Violet and Benny used to live alone in a boxcar. Now they have a home with their grandfather and are spending the summer on their own private island. There is a mysterious stranger on the island with a secret--but that's not the only surprise in store for the Boxcar Children.

Henry, Jessie, Vioet and Benny Alden are brothers and sisters - and tehy're orphans. The only way they can stay together is to make it on their own. One night, during a storm, the children find an old red boxcar that keeps them warm and safe. They decide to make it their home.

Relates the exploits of the four Alden children as they locate a missing man. 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 then untangle the mystery of the two houses.

While having a picnic on the docks, animal detectives Bunny and Jack meet a dog whose one and only lawn chair is missing, and they set out to solve the case.

Seven-year-olds Bradley, Brian, Nate, and Lucy make observations and gather clues that convince them that their older siblings, cousin, and animals have been captured by hungry space aliens.

Henry, Jessie, Violet, and Benny Alden are on another summer trip to visit Aunt Jane at Mystery Ranch. They're thrilled to find their friend Mike Wood lives in the bustling new town near the ranch. But one night, Mike's house burns down and he is blamed for starting the fire!

The Alden children, isolated in a storm at a small bus station, are led into a mystery centering on a polluted river.

The Alden family embark on a trip to an uninhabited South Sea Island. Mike Wood joins them for a holiday full of adventures planned by grandfather. On the island someone seems to be with them. Besides solving the mystery, they have a fine time living so far from civilization.

The Boxcar children must track down an instrument thief in time to save Greenfield's music festival from disaster.

The Aldens investigate the rumors of ghosts, disappearing props and a haunted seat in the Trap-Door Theater.