Nancy Drew Mystery Stories #38: The Mystery of the Fire Dragon book by Carolyn Keene

Eloise Drew asks her niece to investigate the disappearance of her neighbor, a young university student. In New York, Nancy, Bess and George are drawn into the intrigue and danger of a smuggling ring. Nancy plans a clever ruse: George is disguised as the missing Chinese girl! The girl detective is also suspicious of an unpleasant bookstore owner and his loud, overbearing female customer. A series of clues lead the girls to Hong Kong. Ned, who is studying in Hong Kong, joins them. The amateur detectives follow more clues to the international smuggling ring.