One warm night four children stood in front of a bakery. No one knew them. No one knew where they had come from. Henry, Jessie, Violet, and Benny are orphans. Determined to make it on their own, they set out to find a safe place to live. They discover an old, red boxcar that provides shelter from a storm. Against all odds, they make it into their home-and become The Boxcar Children.

The Boxcar children travel to Maine, take canoes into the wilderness and live in a house exactly like the one on Surprise Island, except the Maine house is brown, not yellow. They untangle the mystery of the two houses.