Wayne Dobie is a shy cop whose low-key demeanor has earned him the affectionate nickname "Mad Dog." After Mad Dog saves the life of Frank Milo, a crime boss and aspiring stand-up comedian, he's offered the company of an attractive young waitress named Glory for a week. At first both are uneasy about the arrangement, but they eventually fall in love. However, the situation becomes complicated when Milo demands Glory back.

Former pool hustler "Fast Eddie" Felson decides he wants to return to the game by taking a pupil. He meets talented but green Vincent Lauria and proposes a partnership. As they tour pool halls, Eddie teaches Vincent the tricks of scamming, but he eventually grows frustrated with Vincent's showboat antics, leading to an argument and a falling-out. Eddie takes up playing again and soon crosses paths with Vincent as an opponent.