While visiting Chicago with their grandfather, the Alden children begin receiving mysterious clues to a treasure hunt. Includes related puzzles, games, and activities.

Henry, Jessie, Violet, and Benny hav3e promised Grandfather a vacation from mysteries during their island visit. But the romise proves hard to keep when things start to go missing. Then an old fisherman tells Benny of the island's ghost horse, and late that very night benny sees a mysterious stallion galloping down the beach. Could the ghost horse have something to do with the disappearances?

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.

Strange things are happenikng at the Wagner Farmhouse, and the Aldens' new friends are being blamed. Is the house haunted by the ghost of practical joker Horace Wagner? Or is someonme trying to destroy the museum's chances for success?

A summer spent in doing light housekeeping in a lighthouse proves to be a happy and adventurous time for the Boxcar children, as well as for their neighbor, Larry Cook, who does not want any friends.

The Alden children travel on a Mississippi paddle-wheel steamer to visit an old family friend in his cabin near Hannibal, Missouri, and try to discover who is responsible for the mysterious activities near the house.

When a professional hockey player comes to Greenfield with plans to build an ice skating rink, the Alden children suspect that someone in town wants to stop the project.

When the camp flag goes missing and contest ideas are stolen, the Boxcar Children decide that someone isn't playing fair at the Camp Seagull Olympics.

The Alden children are helping their new neighbors build a tree house when they discover an attic window that not even their neighbors knew about.

While visiting Lake Lucille in the Adirondack Mountains, the Aldens hear stories about a monster in the lake and then encounter evidence that it may be real.