A Promise Paid in His Sin

Synopsis

After my foster younger sister Vivian passed her university entrance exams, our whole family gathered for a celebration dinner. My mother said gratefully to my husband Ethan: "Thank you for helping Vivian get into such a good university." Ethan smiled: "It was my pleasure." After dinner ended, Ethan suddenly spoke in the car: "Do you know why I agreed to help Vivian? On her eighteenth birthday, she came to me herself and said that as long as I helped her, she'd be willing to repay me with her body." My mind went blank. He exhaled a puff of smoke, as if savoring a memory: "Vivian is very obedient in bed. She sounds different from you." My heart seized. I raised my hand sharply and slapped him across the face. "Ethan, you're scum!" My voice trembled, tears welling in my eyes. "She's my sister! How could you do this?" The smile on