Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they're setting off on a wild winter adventure!   The Aldens are helping to map out a new trail on Blizzard Mountain. As the young explorers traipse through a frozen wilderness, they learn that this winter wonderland holds a hidden secret. There's buried treasure somewhere on the mountain! The children begin to search for it—but are they the only ones? Someone is trying to chase the Aldens off the mountain. Is Blizzard Mountain haunted by a snowy ghost, or is someone after the treasure? The Aldens are determined to find out and finish blazing their trail!