In order to take the entrance exam, I had to go to Tokyo and stay at my brother's house. When I got to the house, my brother was nowhere to be found, and my sister-in-law, Hikari, came to greet me by herself. She's always bright and kind, and she's too beautiful for an older brother...I've secretly admired her since the first time I met her. Apparently, my brother is on a business trip for a week, so I'm alone with my girlfriend's sister-in-law... Sister-in-law's big breasts are highly exposed