When Claudia (Jean Marie Barnwell) decided to run away from home, she planned very carefully. She would be absent just long enough to teach her parents a lesson in Claudia Appreciation. And she would live in comfort--at the Museum of Art. For security she invited her brother Jamie (Jesse Lee) to go, too, mostly because he was a miser and had squirreled away a nine-year-old fortune.
The two took up residence in the museum right on schedule. But once the fun of settling in was over, Claudia had two unexpected problems: she felt just the same, and she wanted to feel different; and she found a statue at the museum so beautiful she could not go home until she had discovered its maker, a question that baffled even the experts.
The former owner of the statue was Mrs. Basil E. Frankweiler (Lauren Bacall). And without her help and a consultation in her mixed-up files, Claudia might never have found a way to go home.