Dear Sister

One day, when Hazuki comes home to the apartment where she lives alone, at the entrance she finds shoes that don't belong to her. Though she thought her mother was there, when she came into the room, she found it in a mess. Sensing someone's presence in the back bedroom, she opened the door to find Misaki, whom she had not had contact with for six years, sharing a bed with a man Hazuki didn't know. After that, Misaki decides to freeload in Hazuki's room without permission. Hazuki, who, up until then, had been disturbed in what she wanted to do by Misaki, tries to kick her out several times, but it ends in failure. Also, Hazuki finds her fiancé and Misaki sleeping together in her bed, and the ward office where Hazuki works receives a document about Hazuki through fax. On the other hand, Misaki lives while hiding that she is pregnant, and she writes in a letter ten "Things I Want to Do Before I Die", which she makes progress on. Hazuki fights with Misaki nearly every day, but it later turns out that everything Misaki had done for Hazuki so far was with Hazuki in mind. Hazuki's own love affair, marriage, her sister's pregnancy, childbirth, illness, marriage and more are discovered and broken out one after another, and the relationship between the sisters gradually deepens.