Every time something happens, NATSUKA goes to her cousin Mitsuki's house. As an only child, NATSUKA admires Mitsuki like a sister. Today she is going to Mitsuki's house as well. Recently, her mother remarried, but the stepfather started making advances on NATSUKA, causing her to become distrustful of men. As they discuss it, they gradually enter into a forbidden relationship... "Can girls have sex too?"
