BF-519 Completely Subjective My Sister-in-Law is Yui Hatano

I came to Tokyo from the countryside to visit my brother and his wife during my summer vacation. I met my sister-in-law Yui for the first time in a long time, and she was cheerful, kind, and beautiful, too good for my brother. But then my brother had to go on a sudden business trip, and I was left alone with my sister-in-law Yui...