27 years old, works for a famous interior design company. She looks very glamorous and professional at work, but Hotaru's private life is totally the opposite of what she looks like. She lives alone, and when she isn't working, she's mostly lazing about her rented house in training wear. She's not interested in men. In fact, she isn't interested in anything. "I'd rather lay around than fool around," is her motto.

She gets mad when her boss and landlord, Takano, makes fun of her by calling her dried up fish, because she doesn't like going out and likes to do stuff like staying at home on holidays, reading manga, sleeping, and drinking, just like an old person. It's also because it's been a long time since she last fell in love.

She starts wanting to change her uninterested attitude after she discovers herself falling in love with the young and brilliant Makoto.