It's the end of the nineteenth century in San Francisco's Chinatown, and ghost hunters following the Maoshan tradition of Taoism keep spiritual forces in check. Li-lin, the daughter of a famous exorcist, is a young widow with a burden in the form of yin eyes - a unique ability to see the spiritual world. Her visions and the death of her husband bring shame to Li-lin and her father, a shame their family cannot afford. When a wizard wounds her father, only Li-lin can stop his terrible plans. She can be helped by her peachwood sword, paper talismans and the spirit in the form of an eye, which she hides in her pocket. Among the dangerous alleys of Chinatown, Li-lin encounters evil spirits, bandits and soul thieves, and she must hurry to avoid an ancient evil that will burn the quarter to the ground. She may be the key to everything.