You and your twin always switch places in the past. You fell for your sister's best friend, Jimin. One thing he doesn't know is his friend was you on Tuesdays and Thursdays. You left your hometown because your father remarried. 10 years later your twin and Jimin came to where you're living now. They go to your school. Your best friend, Taehyung has feelings for you but you don't have feelings for him back. Will Jimin knows that you are your twin's sister? What will happen to Taehyung? Will you and your twin switch places again?