Chiba Kuine, Kirihara Akaya's twin sister, suffers from congenital depression. Disliked by his grandfather, Chiba Jiuyin's parents got married despite his grandfather's objection. Later, because of his grandfather's obstruction, he divorced Chiba Kuone's father, Kirihara Sasunari. Ikeda Tomoko sadly left Kanagawa after failing to fight for the custody of their children. Kirihara Sasunari remarried to Haruko, who had been engaged since childhood, under the arrangement of her father. , Then Ikeda Tomoko and Chiba Toshiyuki remarried, fell into the water for unknown reasons, and were found by doctors to have traces of abuse. With the support of her current husband Chiba Toshiyuki, Ikeda Tomoko took Kirihara Kunone back to Tokyo and officially settled in Chiba's home. He studied at Hyōte Elementary School in Tokyo, but Chiba Toshiyuki's son Chiba Shun only loved this sister who showed up halfway.