After ending her failed marriage with her ex-husband Robert (Jarreth J. Merz), Sophia (Harriet MacMasters-Green), who teaches at a university, moved into a new apartment with her daughter Helena (Sabrina Jolie Perez). That morning, Helena's tooth loosened, and Sophia told her daughter the legend of the tooth fairy just like her parents and ancestors. Unexpectedly, the disaster came suddenly in the morning without any warning. The car driven by Sophia accidentally rushed into the river, and her daughter also lost the loose tooth in the car accident. This incident became a turning point in the lives of the mother and daughter. Although they were lucky to survive, something always changed quietly. Helena seemed to believe in the existence of the tooth fairy. She often drew the terrifying figure of the tooth fairy on it, and even spent money to buy milk teeth from other classmates. Sophia was deeply worried about her daughter's changes. She didn't know that they were heading towards a terrifying, cold, and irreversible abyss...