"I think my mother is a killer". Gil So-Myeong, who has excellent grades, good manner, and is an exemplary child, has lived as the perfect daughter according to the standards her mother demanded. However, on the day her younger brother rose from the river as a corpse, a terrifying suspicion rises in So-Myeong's mind. A cruel mother-daughter thriller between a mother who tries to get rid of everything that interferes with her child's life, and a daughter who tries to escape from her!