We went on a graduation trip together as a group of three close friends. I had decided to take this opportunity to confess my feelings to Riho, who I had always liked, and my friends were supporting me...or so I thought. While I was hesitating, unable to find the courage, I heard sweet voices and noises from another room. To my surprise...there was Riho, who had been swept away by the nighttime assault and even allowed me to cum inside her. "I liked her first, so why..." If only I had confessed then! Even as the regret and hatred welled up inside me, my friend and Riho passionately desired each other. She didn't even think about what would happen if she was found out, and even when our eyes met, she pretended not to notice and moaned during intense sex. It was a mistake to fall in love with her.