Mikitaka’s first kiss was Nakadou Ayane. It happened when he was 6th grade. “Hey Mik-kun, You better forget about me someday, Okay?” However, Mikitaka could not forget about Ayane even though they’re not in touch anymore. Mikitaka’s granpa, Genichiro Nakado, died. He was not only a millionaire but also a womanizer. He had many grandchildren, and his will gave them a room in an apartment in the center of Tokyo. Mikitaka went to a high school in Tokyo and started living alone in the apartment and, there he met his cousin Manabe Io, who is the same age as him, and his twin sister Manabe Maya. They, too, have moved to Tokyo to live in one room in the apartment that their grandpa left in. Mikuru unwillingly begins a lively daily routine with the girls, including sleepovers in each other’s rooms. One day, Mikitaka runs into Ayane in the apartment. She was also a resident of the same apartment building. Now in her second year of college, she has grown up beautifully just like in Mikuru’s precious memories. His first love was his cousin who was four years older than him – a sweet and bitter love story.