Relates the exploits of the four Alden children as they locate a missing man. The Boxcar children are determined to solve the mystery that surrounds an old yellow house on their grandfather's property. Strange things have happened in that house where long ago a man disappeared.

The Alden children are staying at the New England farmhouse where their grandfather grew up. There are many stories and legends about the old farm, and there's a woodshed near the house that holds a surprising secret... a secret that dates all the way back to the Revolutionary War!

At the same time that the Alden children's efforts to raise money for a new hospital wing are being sabotaged by nasty tricks, they find their attempts to befriend the new girl Beth frustrated by her strange behavior.

A family starts out on a one-day mountain climbing excursion that becomes very exciting. In fact, it becomes an adventure for the former "boxcar" family. They unearth some mysteries and have a fine time in the process.

The Aldens search for carousel horses that have disappeared from an amusement park.

A friendly writer with a metal detector, the mysterious inhabitants of a tower house, and the discovery of a locket in the sand are ingredients for the Aldens' latest mystery.

The Boxcar Children investigate a mysterious ghost with a glowing pumpkin head at a friend's farm.

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

While canoeing and backpacking near Timberwolf Lake, the Aldens receive strange warnings to stay away from the area and stumble upon clues to a missing cache of stolen coins.

A family, snowbound in a vacation cabin, discovers adventure in surrounding wild life, three children they find in the snow, and a search for a lost recipe.