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. 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...

"The Aldens are helping out at a harvest festival in a town at the foot of the Rocky Mountains. But something in the hills is scaring people away! Are the local rumors about a werewolf true?"--Back cover.

Learning about paleontology and fossil hunting under renowned scientist Dr. Iris Prez while attending summer camp in Colorado, the Aldens investigate an outbreak of strange events that local superstition attributes to a bigfoot creature roaming the valley.

The Alden siblings continue their mission to return lost artifacts around the world to their rightful homes by visiting the Pyramids in Egypt and Stonehenge in England, among other places, while outwitting a thief along the way.