Steelworker Dundee Reilly (Richard Dix) comes to the defense of Mary Malone (Mary Brian), who is being annoyed by a brawny masher. Reilly knocks the cad out, but only later does he realize that he's just k.o.'d heavyweight boxing champion Killer Agera (Jack Renault). Mary's brother Pat (Harry Gribbon) decides to groom our hero for a ring career under the moniker of "Knockout Reilly." There's many an obstacle on Reilly's road to success, including a brief term in jail for a crime he didn't commit, but by film's end Knockout Reilly has won the championship crown himself. Osgood Perkins, the father of Anthony Perkins, is his usual slimy self as gambler Spider Cross. ~ Hal Erickson, Rovi