Ann Clements is terminally ill.

Born with an inoperable tumour in her temple, numerous doctors told her during her childhood that she wouldn’t survive into her adulthood.

Ann’s parents, regarding their frail and sickly young daughter as a hindrance, sent her away to a fancy all-girls’ boarding school, St Cecilia’s, located in the countryside at an early age: ostensibly so the country air could rejuvenate her but, in actuality, to get rid of her.

Ann’s future looked like a bleak, desolate thing – but, by some miracle, she defied both her doctors’ prognoses and her parents’ pessimism.

Ann is now nineteen years old, and her condition seems to have stabilised, despite her frequent headaches. Ann spent so much of her childhood, however, convinced that she would die before her eighteenth birthday that she has no plans, goals, or dreams, and no idea what to do with what remains of her life.

Feeling utterly lost, Ann decides to stay on at her school as an assistant teacher, where she takes care of the more challenging pupils.

Ann’s job is fulfilling enough, but the monotony of her daily routine isn’t enough to satisfy her. As her twentieth birthday approaches, Ann’s desire to experience more of the world beyond St Cecilia’s walls increases…

And then Ann meets St Cecilia’s new nurse, Asaba Kohaku.

Kohaku is everything Ann wishes she was: cool, confident, and fiercely independent.

Though initially afraid of the straight-talking Kohaku, a relationship slowly begins to blossom between Ann and the school nurse. Kohaku tells Ann a little bit about her past, and Ann opens up to her in turn. Eventually, Ann even begins to wonder whether Kohaku might not be the catalyst she needs to escape her self-imposed prison for good.