Akari is just an average teenage girl, ready to start high school. She's pretty plain compared to some of the other girls in class and tends to do everything she can to remain invisible. After all, who needs real friends when you have an imaginary one at home who only thinks about yuri? But when she opens her locker on the first day of high school, she's stunned to find a love letter waiting for her. Except, this isn't an average confession letter--it's a fully filled-out marriage proposal! Even more surprising is that it's from the most beautiful girl in the school, Luna Kiyosumi. What's an invisible girl to do when the most visible girl in school seeks her heart? Panic, obviously!