Dr. Jones, a busy bone-setter, is consulted by Osgood, who is on the verge of nervous prostration. The doctor tells Osgood that what he needs is relaxation, and offers him two tickets to the opera. Meanwhile, Michael Clancy, a plumber, is engaged in fixing pipes in the doctor’s cellar. Mary Fagan, a cook in the doctor’s household, indulges in a flirtation with the plumber, and provides him with a substantial meal. Mrs. Osgood phones to the plumbing office, and the boss plumber sends Clancy to Mrs. Osgood’s house to fix the radiator. Clancy, before starting on his mission, reads in the newspapers of a diamond robbery, characterized as an inside job, carried out by burglars who got away with the loot, amounting to $100,000. He confides to one of his associates that he’s going to be a burglar, as it doesn’t pay to be honest. When Clancy arrives to fix the radiator Mr. Osgood, not knowing how to get rid of the opera tickets, offers them to the plumber, who expresses his preference for a burlesque show and declines the tickets. The plot thickens when Mary, the doctor’s maid, arrives with a note from her employer addressed to Mr. Osgood. Osgood admits the maid, and, noting that she is pretty, gives her the tickets. Mrs. Osgood learns from the letter that the maid has handed to her that the doctor presented the tickets to her husband with a view to affording him relaxation. The maid confides to her that the tickets were given to her by her spouse. Osgood is denounced as an inhuman wolf who is seeking to prey on poor working girls. At the plumber’s office later, Clancy is cutting a mask out of his apron. Mary telephones to him that she wants him to take her to a swell joint that evening. Clancy, bent on committing burglary, phones back to her that he is going to work overtime that evening. Mary becomes angry and throws the envelope containing the tickets out of the window. We next see Mrs. Osgood telephoning to her husband at his office that she wishes him to accompany her on a visit that evening to her sister who is seriously ill. Clancy deems it wise to make his peace with Mary, and rushes off to the doctor’s house, where, just as he is about to enter, he runs across the envelope containing the tickets. He decides that Osgood’s failure to attend the opera that night will block his dark plans. So he proceeds to the Osgood establishment and hands the tickets to the butler, who, in turn, hands them to his master. Osgood, delighted to square himself with his wife, exhibits them, but Mrs. Osgood, woman-like, turns on him. Mrs. Osgood thereupon presents the tickets to the butler, who offers to give the cook an operatic treat. The cook, however gets the impression that he is trying to “kid” her and gives him a black eye with the rolling pin. The butler hastens to have his eye treated by Doctor Jones, and incidentally throws the tickets down on the doctor’s desk. The doctor recognizes the tickets and is surprised to have them returned. That evening Clancy arrives at the doctor’s house to pacify Mary. He drops his improvised mask in taking out his handkerchief. Mary catches a glimpse of the mask and picks it up as she shouts at the plumber: “So you was goin’ to a masquerade ball with another woman.” Clancy has a hard time to bring Mary around, but finally he convinces the belle of the kitchen that he is plumb gone on her, and she consents to become his life-long mate.