I am a married person, Natsu is the one who is about to get married. Unfortunately, this business trip encountered heavy rain, so Natsu immediately invited me to a hotel to shelter from the rain. There was no other way, so I had to stay. But Natsu was constantly charming and made me irresistible. And since then, every time we go on a business trip and it rains, my sister and I find a place to shelter from the rain and indulge in sex. Gradually, my affection for her grew more and more, I wanted to be with her more, I just hoped that it would rain just when the two of us went on a business trip. But it seems that it is just because I am polyamorous. You don't want me to be serious about this. Some time later Natsu got married, and our relationship ended there, too...