Miku Takanashi has lived alone with her father, Jinbe, since her mother's death. On her 20th birthday, Jinbe tells her that he made a promise to her mother to raise Miku as his own daughter. In other words, he's not Miku's real father. Feeling as though she cannot live under the same roof with him anymore, Miku sets out on her own. Jinbe confides in a co-worker that lately, he's been seeing Miku less as his daughter, and more as a woman.