Can you help me find this book for my mother? She says it is a story about a King who has a son. The King's brother wants the boy murdered so the ?Mandarin servant runs off with him to safety, flees to ?USA and they have nothing to live on, but servant sets up a business. Servant gets sick and goes to hospital, whereupon when they take his clothes off, they discover he was a woman all along - she dressed as a man in order to make the long rescue journey in disquise. My mum seems to think it was called something like The Chinese Mandarin", but I'm not so sure of this. Please can you help. The book could be quite a few years old.

Mu Lan