Su Nian was frail from birth and abandoned at an ancient temple. She was raised by her adoptive parents. At the age of twenty-one, she suddenly felt dizzy in her university library, and from then on heard fox cries every night. One midnight, an injured white fox broke into her bedroom and made a pact with her: it would use her body to heal its wounds, and help her accumulate merit.
From then on, she could see the spirits of the dead and hear their grievances. Working with criminal investigator Jiang Ye, she guides spirits to their rest, solves cold cases, and suppresses evil forces, all while gradually uncovering the mystery of her own origins. It turns out she was born with the mission of protecting the mortal world and vanquishing demons, and the white fox is the Dao companion from her past life who has waited three hundred years for her.
