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?

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.

Four orphaned children run away and live in a boxcar, until they are found by their grandfather. Includes a biography and photographs of the author.

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.

Henry, Jessie, Violet, and Benny are given the opportunity to be extras in a movie about the Alamo, but they are called upon to use their sleuthing skills when Claire, the star of the film, is implicated in the theft of a valuable ring.

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.

While visiting a friend of their grandfather's on Sullivan's Island, off the coast of South Carolina near Charleston, the Boxcar Children encounter mysterious activities related to rumors of a buried pirate treasure.

The Aldens are excited to be playing in their summer soccer league, until someone begins sabotaging the teams.