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 used to live alone in a boxcar. Now they have a home with their grandfather, and they’re going to visit the castle!
 
Built long ago, the castle is now being turned into a museum. As the Boxcar Children help to restore it, they see mysterious lights and hear strange music. Faces appear in windows- and then disappear. Can the children solve the mystery hidden within the castle walls?