As a critical care doctor, Jessica Zitter has seen plenty of “Hail Mary” attempts to save dying patients go bad—attempts where doctors try interventions that don’t change the outcome, but do lead to more patient suffering. It’s left her distrustful of flashy medical technology and a culture that insists that more treatment is always better. But when a new patient goes into cardiac arrest, the case doesn’t play out the way Jessica expected. She finds herself fighting for hours to revive him—and reaching for a game-changing technology that uncomfortably blurs the lines between life and death.