“Once upon a time, in sunny California,” a title card announces through the rain, lived toy manufacturer Fred MacMurray with his perfect fairy-tale family: bustling wife Joan Bennett and three busy children. Left home alone one evening, he answers the doorbell in an apron, and there stands Barbara Stanwyck after twenty years, carrying memories and a carefully hidden torch. “Sure I’m happy,” MacMurray says haltingly, showing Stanwyck his latest creation, Rex the Walkie-Talkie Robot; she shows him a brave face shadowed with loneliness. While MacMurray indulges in fantasies of youth regained, Stanwyck beautifully conveys the ambivalence of an ethical person who wants what she can’t have. (She’d never get it anyway, with those nightmarish children spying around corners.) Douglas Sirk’s brilliance is to recognize both the horror and the wisdom of accepting one’s lot. When MacMurray finally claims, “I’m all right now,” it’s either one of the most devastating lies in cinema or, even worse, true.