This is book number 23 in the The Boxcar Children Mysteries series.
Aunt Jane takes the Aldens to stay with her friend, Kay, who owns an old, shabby motel in Florida. Kay is ready to sell the motel, when the children offer to help fix it up and put it back in business. But they soon learn that someone is trying to make sure it stays out of business . . . forever.
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.