A married woman living with her much older husband and her stepson finds herself restless with her mature body, while the son, having ended up with a mother younger than him, can no longer suppress his twisted desires provoked by his vulnerable mother's unconscious advances. One day, the son secretly watches his parents' intimate moment after a long time, and takes advantage of his dazed mother to play a mischievous prank on her body. From that day on, an abnormal relationship begins, escalating day by day. The son eventually exposes his mother's bowel movements in front of his friends, driving their taboo bond even deeper.