Relates the exploits of the four Alden children as they locate a missing man. "Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather and are determined to solve the mystery that surrounds an old yellow house on his property. Strange things have happened in that house where long ago a man disappeared. When the Boxcar Children explore the house, they find an old letter written by the brother of...

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.

The Boxcar Children, now living with their grandfather, spend the summer on their Aunt Jane's ranch. Their aunt seems quite unhappy until at the end of the summer a surprise discovery brings happiness to all

The Alden children meet Mike Wood and a strange chain of events begins. Mike's house is mysteriously burned down, a man in a blue hat appears, and the Alden's uranium mine is in danger of being sabotaged. The four children solve the mystery.

At an old library, the Alden children discover a boy who needs their help and a stranger who is after a valuable object they found in the library

Two brothers take summer jobs at a department store where a series of peculiar events brings them under suspicion

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

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