The former World Heavyweight Champion Rocky Balboa serves as a trainer and mentor to Adonis Johnson, the son of his late friend and former rival Apollo Creed.

Hillary Kramer, a successful Perfume magnate, awakes one morning to find that her accountant has robbed her blind and left for South America. Going through all of her remaining assets she finds a boxer, purchased as a tax write-off. She decides to take Kid Natural, Eddie Scanlon, who is much more at home giving driving lessons, into the ring and use him as her key to riches. Eddie thinks this will only get him killed and resists.

Gruff boxing manager "Square Shooting Murph" Murphy manages a naive boxer from Indiana, Homer Baston.Homer is willing to give up his boxing career searching for his parents, so Murphy hires two jailbirds to play his long lost parents to keep him in the ring.

This Universal programmer was based on a Collier's Magazine story by journalist Quentin Reynolds. This story in turn was ostensibly based on a true incident, in which a gangster "returned from the dead" to save an innocent young man from the electric chair. The nurse of the film's title is Katharine McDonald, who falls in love with her prizefighter-patient Lee Burke as he recovers from a beating received in a fixed prizefight. Katharine must fend off the advances of criminal attorney John Dodge, another patient who also loves her and becomes jealous of Lee. But when Lee is framed for the murder of his disgruntled manager, Slice, by a henchman of the fight-fix leader, Joe Largo, Dodge takes on his defense and works with Katherine to discover the real killer. Convicted and sentenced to death, Burke is about to walk the "last mile", as Katharine encourages mortally wounded Largo to a deathbed confession.

The boys are working at the local boxing arena where their friend, Jimmy Higgins, is boxing. During a crooked match Jimmy is killed. The boys seek out his older brother, Johnny, a former boxer who gave up the sport rather than go crooked, and help train him to get back in the ring. They try to get him a shot at the title, and when they do the same crooked gangsters that were behind Jimmy's death try to get Johnny to take a dive.