Pierre de Brezeux, a young man of wealth and refinement, becomes engaged to a beautiful and worthy girl of his station in life, Marthe Rozay. Pierre has one fault, weakness, and this is the cause of becoming entoiled with a dancer, Ida Bianca, who has determined to win him. In spite of his infatuation, Pierre really wishes to be true to his fiancée, but with arts and wiles the dancer keeps him at her side. One day he is persuaded to take Ida to dine openly in the Pavilion du Bois, in the Bois de Boulogne. It is a fatal step, for he is seen and his enraged fiancée, wounded to the heart, breaks off the engagement in an interview the next day, in which Marthe shows herself more grieved than bitter. So Pierre is tighter in the wiles of Ida than ever. Ida, conscious that she is the aggressor in the love affair, endeavors to make him jealous by flirting with Novita, a famous matador. Novita is the one to become jealous, for he falls in love with her with sudden violence, and she delights in torturing him. Pierre proposes to Ida a motor trip to Spain, and the beauty of the scenery and the pleasure of the trip make them happier than they have been before. Running out of gasoline, Pierre stops a passing car and requests a small supply, which is granted. The occupants alight and Pierre finds himself face to face with Marthe. Their embarrassment is increased by Ida's disdainful attitude. Pierre suffers badly and on arriving in Madrid, writes Marthe a letter of apology and tells her if he had been warned, the regrettable incident would not have happened. Marthe is grateful, for the note tells her that Pierre's self-respect is not yet dead. In Madrid Ida renews acquaintance with Novita, who begs her to leave Pierre. She refuses for the time, in spite of the fact that her love for Pierre is waning. Finally Novita writes her a note on the eve of a great bullfight, telling her that unless she can give him hope he will throw himself, the next day, upon the horns of the bull. If she holds out hope to wear violets at the bullfight. The note is delivered at the hotel to Pierre in Ida's absence. He puts it in his pocket and forgets it. On the morrow he attends the bullfight with Ida. Novita, failing to see the violets, keeps his promise and the terrible tragedy totally unbalances Ida. She shows her love for the dead matador plainly, and when Pierre, remembering at last the letter, gives it to her, her anger knows no bounds. After a terrific quarrel, they part, and Pierre realizes fully for the first time, all he has lost by his entanglement with the woman and the depth of his folly.