47-year-old full-time housewife Nao Hayashi receives a sudden call informing her of her son's deteriorating grades. With graduation—let alone employment—in jeopardy, the homeroom teacher decides to conduct a home visit. Desperate to secure her son's future, Nao pleads for mercy, only for the teacher to present her with a disturbing demand. Gradually, Nao begins to comply with his requests—until one day, her son's friend witnesses the scene. The relationship between mother and son unravels, exposing the teacher's true, sinister intentions.