Because they do not want to be separated, four orphaned children run away and live in an old abandoned boxcar

When their grandfather arranges for them to spend two weeks at Sunny Oaks, the four Alden children enjoy settling into the routines of farm life but become suspicious about a mysterious horse locked in the stables

While volunteering at a rescue ranch, the Alden children investigate the disappearance of a few horses.

The Aldens' dog, Watch, comes across a mysterious box with a note inside, a box that is part of a game called Geocaching. Henry, Jessie, Violet, and Benny join the game but soon suspect one of the members of the geocaching club is a thief.

"The winter sports season is here, and the Aldens are excited about all the snow activities--especially snowboarding. But soon they find themselves in the middle of a mystery surrounding a star athlete and a stolen snowboard"--

Taking a shortcut through the Greenfield Cemetery, the Aldens stumble across a local superstition which maintains that visitors are required to leave gifts or suffer the wrath of a malevolent ghost, a suspicious tradition that prompts the children to expose the truth.

In the year before they become the orphans known as the Boxcar children, Henry, Jessie, Violet, and Benny Alden live with their parents at Fair Meadow Farm, where, although times are hard, they take in a family who has been stranded in their car during a blizzard.