Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they are visiting the Crooked House, Mrs. McGregor's childhood home in the snowy countryside.   When Mrs. McGregor, the Aldens Housekeeper, learns that she cannot afford to keep the Crooked House, the Aldens want to help. Mrs. McGreggor tells them that ever since she was a little girl, there was an unsolved riddle about the house. And solving that riddle could lead to a treasure! Could the treasure save the Crooked House? Can the Boxcar Children find it in time?