The sexual voraciousness of newspaper heiress Grace Caldwell threatens to destroy the reputation of her wealthy Pennsylvania family. As a precocious teenager, she is assaulted in her room in her own house by her older brother Brock's friend Charlie Jay, to whom she finally yields willingly, the first of a long series of lovers. Grace understands her weakness but goes on in her path of seduction, until she meets San Francisco real estate broker Sidney Tate at a Christmas party. The two fall in love and he proposes marriage. Grace confesses her past but despite being taken aback, Sidney marries her and she commits herself to a relationship, a pledge she keeps for the first few years of their union, which produces a son and a seemingly idyllic life on a farm.

Problems ensue when lusty contractor Roger Bannon, the son of one of her mother's former servants, confesses to Grace he's been in love with her for years. An affair ensues and when she eventually ends it, he becomes enraged, gets drunk, and accidentally crashes his truck, killing himself. Reports of his death include details about his tryst with Grace, rumors which reach her husband. Under pressure, Grace admits her guilt to him and swears it will never happen again. At this point, however, the wife of newspaper editor Jack Hollister, who is also in love with Grace, makes a scene during a charity ball accusing Grace of seducing her husband. Sidney, who witnesses the scene, is once more convinced that his wife has lied to him and goes away. Grace runs after him, swearing she had nothing with Jack Hollister. Still, Sidney departs, leaving her behind in a state of despair.