The Perfect Bloodstream [KanameKuran]

"I think I might have inhaled you, I can feel you behind my eyes. You've gotten into my bloodstream, I can feel you flowing in me." Twins. One was engaged to their brother, Kaname Kuran. The other left for nothing, but to watch. Both love, and loved him, as well as Zero. Kazumi and Yuki Kuran, who are now known as the Cross sisters, fight for their love for Kaname and Zero. Who will end up with who? And what happens when they get closer, and closer to the truth about their dark and dangerous past? Will they run away or will they stay?