Maria Barker, wife of foreign diplomat Sir Frederick Barker, feels neglected at home. Unknown to her husband, Maria flies to Paris to visit Grand Duchess Anna Dmitrievna, who runs a salon. While there, Maria meets Anthony Halton, who, immediately enchanted by her, invites her to dinner. Because Maria refuses to give her name, Anthony calls her "Angel" and fervently longs to see her again. Maria refuses to maintain contact and returns home, there attempting to regain her husband's attentions. Frederick, however, is completely preoccupied by his work. At the races Frederick encounters Anthony, with whom he had a brief acquaintance during the war. Anthony relates his story about "Angel," intriguing Frederick, who invites his old friend to meet his wife. Maria and Anthony maintain a proper demeanor in Frederick's presence, but when alone together, Anthony implores her to meet him once again. Later, Frederick learns about Maria's first trip to Paris and, missing a Geneva convention, goes to Anna's salon to find out the truth about his wife. He finds Maria there and learns that she is the "Angel" of whom Anthony spoke. Maria is forced to choose between the two men, and decides to return to her husband.