Even before we got married, my wife's younger sister, Rei, often played together. I thought she was cute, but I never realized it as a member of the opposite sex. Until that day... Three years after I married my wife, one day I had a fight with my wife and left the house, but I came to Rei's house without any need to go. "Hey... why did you marry your sister? Can't you do it?" I thought I was kidding...Rei-chan boldly seduced me... and I couldn't refuse.