Nanami Kawakami MEYD-561: Living with her sister-in-law, who pretends to be aloof in front of her brother, in a tsundere-like relationship.

My sister-in-law, Nanami, was always cold to me. Although beautiful, she was difficult to deal with. One day, she found out I was watching porn, and she ended up watching it with me, and we even had sex. Thus began our secret life as friends with benefits…