In this novel of harrowing suspense and superbly-crafted plot twists, author Tess Gerritsen draws on her years of experience as a doctor and delivers an explosive debut thriller. A second-year resident selected for Boston's Bayside Hospital's elite cardiac transplant team, Dr. Abby DiMatteo is just beginning to learn the nightmares involved in finding a donor heart. She makes a life-or-death decision and gives a harvested heart meant for an older wealthy private patient to a dying teenager instead. When another donor heart suddenly appears without the proper paperwork, Abby defies the hospital's demands for silence and begins her own investigation that reveals a murderous, unthinkable conspiracy -- and uncovers some horrifying clues as to where the mysterious organ was harvested.