My sister was nothing like my girlfriend. Her appearance, her personality—everything was different, as if they were completely different people. She always acted kind and caring toward her younger sister, but behind that facade, she had a bold and seductive side. My feelings for her grew uncontrollable, and I couldn't resist giving in to temptation. After that, I began stealing secret moments with her whenever my girlfriend wasn't looking. The more I told myself it was wrong, the more intense my emotions became, and I fell deeper under my sister's irresistible spell.