Tsubasa Uehara and Arisa Sonoda are identical twin sisters separated by their parents' divorce three years prior. Having only been able to communicate through secret letters, the two arrange to meet up with each other at a park in which they used to play. Nicknamed the "Demon Princess" of her middle school, the tomboyish Tsubasa struggles to get along with the other students in her class. In contrast, the feminine Arisa is the perfect class representative who achieves good grades and has many friends. Learning of her twin sister’s envy, Arisa proposes to Tsubasa that she attend school in her place. Upon returning from school that day, Tsubasa recounts how amazing her experience was to Arisa, who is horrified to learn that she is still jealous of her life. Telling her sister that she knows