At the center of the story is the mild teacher of ancient letters Ottavio Camaldoli, who undergoes a heart transplant, without knowing that the organ comes from a ferocious delinquent, who died killed, who expressed, as a last will, that of being avenged by him who will receive his heart as a gift. Poor Ottavio, however, has no intention of becoming a murderer, but will force him to make choices, revealing our deepest nature.