Sergeant Joseph Andrew Bomowski (Sylvester Stallone) is a tough cop. His seemingly frail mother Tutti (Estelle Getty) comes to stay with him and progressively interferes in his life, driving him crazy. After cleaning his gun with bleach and finding out she ruined it, Tutti buys him an illegal MAC-10 machine pistol, and witnesses the murder of one of the men who sold her the gun. Tutti is taken to the police station to give a statement, and starts poking around in Joe's cases. She learns the gun she purchased was part of a collection taken from a burned building, and the gun insurance money was received.