Five years ago, in the Kamikaku Island incident, she lost both her parents and her memory. The island was completely wiped out, and she was the only survivor.
Her wealthy maternal grandmother took her in. Her grandmother was worried about her and did not want her to have to commute to school, so she had her educated at home by tutors.
Eventually, knowing that she herself might not have long to live, her grandmother enrolled her in a girls' residential school, Kaihou Academy. Enrolled against her will, she misses her home, She can't hide how she feels distressed.