At the beginning of the novel, the main characters, Claudia and Jamie Kincaid, run away from home and decide to live in the museum. In the process of exploring the museum, they stumble upon Mrs. Frankweiler's secret living space. Mrs. Frankweiler is a kind and eccentric older woman, and she allows Claudia and Jamie to stay with her in the museum.
As the novel progresses, it is revealed that Mrs. Frankweiler has a deep love and connection with the museum. She has been secretly living there for years, and she knows every nook and cranny of the place. She is also a talented artist, and she creates beautiful sculptures and paintings that she hides throughout the museum.
Through her relationship with Claudia and Jamie, Mrs. Frankweiler is able to share her love of the museum with others. She teaches them about the history and art of the museum, and she helps them to appreciate the beauty and wonder of the world around them.
In the end, Mrs. Frankweiler's secret is discovered, but she is allowed to continue living in the museum. She becomes a beloved member of the museum community, and she continues to share her love of art and beauty with others.
The connection between museum and Mrs. Basil E. Frankweiler is a central theme of the novel, and it highlights the importance of art and culture in our lives.