Miku doesn't wear a bra when she's at home. The problem for her father, who has a daughter like that, is that even though they are part of the family, seeing the breasts of a daughter her age every now and then is bad for her heart and crotch. What's more, Miku senses this and acts as if to seduce her father...and her father finally puts his hands on Miku's braless bust!
