Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they're fixing up the old Bugbee House, a spooky mansion in their neighborhood!   The Aldens are helping the Heart and Hands group restore an old estate. The house is bursting with collections of its mysterious and eccentric former owner. But when the contents of the house are auctioned off, the Aldens discover that much of the collection is missing! And that's not the only mystery awaiting the Aldens in this strange mansion. As the children explore, they come across hidden rooms, secret passageways, and strange noises coming from the walls. The Aldens are determined to learn the secret of the Bugbee house . . . but are they the only ones?