Joe, a good natured Italian, runs a basement ice, coal and wood establishment in the cheap Italian “East Side.” Trina, daughter of old Capino, a cobbler, lives next door. She is fond of Joe and is relieved when she learns that Joe’s “sweetheart,” who arrives from Italy, is none other than his little old “Mamma Mia,” his mother. Godfrey Kelland, district attorney, is a candidate for the governorship, and Joe’s sympathies and efforts are enlisted in his behalf. The Weasel, a notorious crook, is arrested as he seeks refuge in Joe’s house, and suspicions are cast upon Mamma Mia. Just at this time Mrs. Kelland loses a diamond pin which is discovered in Mamma Mia’s possession. Baby Kelland has placed the pin in the basket of clothes which Mamma Mia is to wash and she is found “guilty” and sentenced to two years in the penitentiary. In the meantime, Joe and his mother have witnessed an attempt upon Kelland’s life and assisted him, but nevertheless Kelland is vigorous in his prosecution of Mamma Mia. A little later Mrs. Kelland discovers the baby putting another piece of jewelry in the basket and she decides that Joe’s mother is innocent. Two crooks from the gang determine to put a stop to Kelland’s activities and to “plant” a golf ball filled with nitroglycerin so that Kelland will be blown up as by an unknown accident. They play upon Joe’s feelings and induce him to place the ball. Just as Kelland is about to strike the ball, Mrs. Kelland and Trina come into the grounds, and to save them Joe takes the blow upon his own body. Joe’s confession that the ball was intended for him incites Kelland’s anger, but Mrs. Kelland’s story of the baby’s innocent part in the tragedy, and her pleadings, soften the politician’s heart, the little Italian family is reunited and Trina’s happiness also secured.