This is book number 36 in the The Boxcar Children Mysteries series.
Henry, Jessie, Violet, and Benny are going to visit a 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’s walls?
The Boxcar Children Series was created by Gertrude Chandler Warner, a teacher, when she realized that there were few, if any, books for children that were both easy and fun to read. She drew on her own experiences in writing the mysteries. As a child, she had spent hours watching trains near her home, and often dreamed about what it would be like to live in a caboose or freight car. In each story, she chose a special setting and introduced unpredictable, unusual or eccentric characters, to help highlight the Aldens’ independence and resourcefulness. Miss Warner lived in Putnam, Massachusetts until her death in 1979.