A step-sister suddenly appeared due to my parents' remarriage. I, who was raised in a household of men, have a bewildered daily life wondering how to interact with her. My step-sister, who has no idea about my feelings, seems to naturally not see me as a man, and she exposes her unsightly figure without any caution with an unbelievable distance, so I can't stand it. One day, in front of me, she puts on tight clothes and shows off her too-raw, plump ass lines as much as possible...