Ichirou Akiyama, a 16-year-old high school student at the Hanabizawa High. His dream was being able to have a girlfriend and to find his other twin sister. A smart girl named Naoko Hamasaki with a cute smile transferred to where Ichirou started his school. Suddenly Ichirou found that he had a crush on her, so he started with a conversation while going home. They started dating after months and months, but he had a feeling that Naoko Hamasaki is his twin sister, what would happen to their relationship if they both found that they are twins?