On their way home from a carnival, Duke Lambert and his family and guests narrowly escape death in an auto accident caused by a mysterious shadow. At Lambert's Villa Felicitá, Lambert and his son Corrado, who is in love with Grazia, the daughter of Princess Maria, urge Grazia to marry Corrado soon. Grazia, however, is reluctant to marry because she has not yet experienced the kind of happiness for which she longs. While alone in the garden, Grazia screams and faints when she senses a mysterious and malevolent presence, but sees no one. The garden is searched for an intruder, but when no one is found, everyone but Lambert retires early. The presence reveals himself as Death to Lambert and demands that Lambert accept him as a guest while he takes a three-day holiday in mortal form to discover why men cling to life. Death insists that Lambert reveal to no one his true identity when he appears in the form of Prince Sirki, a friend whom Lambert was expecting and who, unknown to him, recently died. As Death leaves the house, Corrado shoots from an upstairs window at what he belives to be the intruder, but to no effect. The sound of the gunshot awakens the household, and Lambert attempts to prepare them for the strangeness of their new guest, Prince Sirki, who arrives shortly thereafter. The newness of his mortal form delights Death, and he behaves like a gentleman. Death and Grazia are immediately smitten with each other; however, she goes home with her mother, and Death is entertained by Lambert's guests, Stephanie and Rhoda Fenton, who are hungry for husbands. In the meantime, accidents occur all over the world, but to everyone's amazement no one dies. Gradually, Death realizes that love is the most important human emotion, but remains free from its pull, as all the women he encounters sense Death's strangeness and are frightened of him. Grazia returns to the villa on the eve of Death's last night in human form and remains willing and unafraid as Death makes love to her. Now anguished at having to leave his newfound humanity behind, Death consents to the pleas of Lambert and the others that he leave Grazia behind, but Grazia, it transpires, already knows the true identity of the man she has taken as her lover, and she and Death depart joyfully together.