We learn that Cai-Li is back at the school because his younger brother needs a heart-to-heart transplant. He begs Cai to use his heart and give Cai-Ling a new one, because he's the same race as his brother. Cai says he can't do it, since he'll die if he does, but he begs to be allowed to do it anyway. He's willing to risk his life for his brother's sake.