"If you don't come over, I'm going to tell my brother we had sex." Yukina was working on the front desk at a hotel when Hiroki, the grandson of the CEO, fell in love with her at first sight. Now they're engaged, and she's filled with happiness because he's kind and takes good care of her. But, Yukina has a deep, dark secret... She's having an affair with Hiroki's younger brother, Wataru...... One bad mistake leads to an abnormal relationship between Yukina and the two brothers...