Madame Hoo spends a lot of the book without a voice. She emigrated from China as Mr. Hoo's second wife—although we never really figure out why she married him—and doesn't speak very good English. It's no surprise she feels alone and alienated in Sunset Towers.
Maybe it's no surprise, either, that she turns to a little light kleptomania as a means of saving up for a ticket back to China:
Madame Hoo knew from the shifting eyes that a bad person was in the room. She was the bad person. They would find out soon. The crutch lady had her writing-book back, but all those pretty things she was going to sell, they wanted them back, too. She would be punished. Soon. (24.9)
We can understand a pearl necklace and gold watch, but it's a mystery why she's so interested in Turtle's Mickey Mouse clock—maybe she just loves Disney? She spends most of her time staring out the window at the lake, wishing she could see back to China.
Madame Hoo is also culturally misunderstood by both her husband and Grace Wexler, dressed in stereotypical, revealing clothes, and limited to pouring tea at the Hoos' restaurant:
Madame Hoo served in a tight-fitting silk gown slit high up her thigh, a costume as old-fashioned and impractical as bound feet. Women in China wore blouses and pants and jackets. That's what she would wear when she got home. (16.2)
But when we see her at the end of the book as the confident English-speaking Sunny, who's running a successful business by herself and takes a trip back to China on her own steam, we're pleased for her—she overcame the odds and finally became comfortable in a strange land.