Hagino, along with her husband, daughter Moeka, and the three of them, moved into a pre-owned detached house. For someone who wasn't blessed with her own family, this was the happy family she dreamed of. However, one day, while Hagino is out, she receives a phone call from Moeka, with a desperate voice, seeking help. "Buy some shortcake and coke." Hagino rushes home and sees her house in ruins, Moeka's clothes torn to shreds, and a strange girl straddling Moeka, gripping a large pair of scissors. The name of that girl is "Chi-chan." She used to live in this house, but she was supposed to have left town after causing a certain incident. Her presence exposes the "poison" that the seemingly happy Hagino family was trying to hide, heralding the beginning of nightmarish days...