Madam White and Xu Xian married within the month. She was perfect: beautiful, gentle, skilled in medicine. Together they opened an apothecary that healed the poor for free.

The people of Hangzhou adored her. She organized festivals and knew everyone's name. She was kind to the children and patient with the elderly. Xu Xian, watching her from across their modest shop, sometimes could not believe she had chosen him.

One man saw through her human form: the monk Fahai of Golden Mountain Temple.

"Your wife is a white snake demon," Fahai told Xu Xian directly. "She has deceived you."

Xu Xian refused to believe it. Who would believe such a thing about the woman who had given him tea every morning and tended his fever when he was sick and cried when he was sad?

Fahai nodded — this was always the response, it seemed — and withdrew. But he did not leave. He simply became patient.

Patience, in the end, is always the monk's greatest weapon.