Gathering all the courage I could muster, I confessed to my well-mannered, top-performing classmate—and unbelievably, she said yes. I finally had my first girlfriend. But then, my childhood friend from next door, one-year-older Minami nee-san, suddenly changed completely! She's determined to claim my virginity for herself... No way! I already have a girlfriend! Yet, my first time happens at school... even though I'm with someone else... with my childhood friend's older sister... The thrill is so intense that—wait—why can't I get excited during this long-awaited sex with my actual girlfriend!?