Himari doesn't wear a bra when she's at home. Is it because she hates being constricted, or is it for relaxation? The brother who has such a sister has been recently troubled by this matter involving Himari. No matter how much they are family, frequently seeing the breasts of a sister around his age is bad for both his heart and his crotch. However, the more he becomes aware of it, the more wrong thoughts cross his mind...
