Hagino, her husband and her daughter moved to a second-hand house. One day, Hagino, who was out, received a call for help from her daughter Moeka. Hagino hurried home to see the abandoned house, Moeka with her clothes torn, and a strange girl riding on her. Her name is Xiaoqian. She used to live in this house, but left the city because of something that happened. Xiaoqian's existence exposes the "poison" that Hagino's family, who seem to be happy at first glance, want to hide.