Yasuko is a normal girl who tends to be overshadowed by her younger sister, Ayaka, who intentionally antagonizes her. Yasuko suspects something is seriously wrong with Ayaka after their mother reveals that Ayaka's appearance began to change significantly after her first year of life, and seeing multiple girls around town who look exactly like her. When a severely disfigured Ryo gets in contact with her and reveals the truth about Tomie, Yasuko agrees to help him trap "Ayaka" and keep her contained. The two spend decades guarding Tomie.