Park Seonga is eighteen. By day, she's a high school senior preparing for exams; by night, she's a shaman who drives away evil spirits. After five years of living a double life, all she wants is an ordinary romance based solely on looks.
Then a man walks backward into the ritual hall. Bae Gyeonu is a prodigious young archer with a face that makes Seonga forget her incantations at once. Unfortunately, to a shaman, someone walking backward means only one thing: death is near. A hundred-year-old evil spirit named Bong Su has taken up residence inside him, devouring his life and the luck of everyone around him. The whole school thinks he's a walking disaster. He thinks of himself as already dead. He's lived to eighteen without believing in gods, asking anyone for help, or ever having someone truly hold on to him.
Seonga decides to save him within twenty-one days. What she doesn't know is that her body itself is a talisman. Every touch can briefly call Gyeonu back from the evil spirit, but every moment of closeness hastens the loss of her own life. A shaman who wants no trouble, a boy who doesn't want to be saved, a century-old evil spirit that can't bear to leave the human world, and a childhood friend who hides his affection in spicy rice cakes. A heart rests within the talisman, along with the resolve to protect someone.
But the law of equivalent exchange never shows mercy. What will she have to give up to save his life?