Southpaw boxer Jimmy Dolan [Douglas Fairbanks Jr.] projects an image of clean living outside the ring, but behind that polished façade he can be a wary cynic when no one is watching. After a fight, a blonde allure named Goldie West [Shirley Grey] gets him drunk, setting off a chain of events that bring him to the edge of disaster. When a reporter named Magee [George Meeker] plans to write about Jimmy’s behavior, a sudden punch in the face accidentally ends Magee’s life, leaving Jimmy facing serious charges.
With the prospect of jail looming, Jimmy’s manager Doc Woods [Lyle Talbot] bolts with his money and watch, fleeing with Goldie in a fiery car crash that kills them both. Doc’s face becomes unrecognizable, and since he’s wearing Jimmy’s watch, the police assume the boxer is dead. A sharp-eyed detective, Phlaxer [Guy Kibbee], remains unconvinced and has his own ambitions: he needs one big score to salvage his career and pension, and Jimmy—alive or not—could be the key to that plan. The twist about the watch being on the wrong wrist for a left-hander only deepens the mystery.
Jimmy, desperate to reinvent himself, disappears. Starvation and necessity push him toward a small farm run for crippled children, where a young woman named Peggy [Loretta Young] and her Auntie [Aline MacMahon] quietly tend to the kids. He lends a hand, finding purpose and kinship among the workers and the children, and gradually becomes part of their tight-knit circle.
To keep the farm afloat, a charity boxing match against the fearsome King Cobra [Sammy Stein] is arranged, with the bout framed as a chance to save the mortgage and give the children a better future. A photograph places Jimmy under the assumed name Jack Daugherty, making it clear to Phlaxer that the fugitive Dolan is very much alive. The fight begins roughly, but Jimmy digs deep, drawing on his resolve to raise funds for Peggy’s cause as the rounds accumulate.
At a tense moment in the final stretch, Phlaxer sits in the front row and smiles, revealing that he recognizes the boxer’s true identity. He quietly says, "I know who you are, southpaw!" and the moment becomes a turning point. The display of grit and heart fuels Jimmy to rebound and fight with renewed intensity, though exhaustion finally lands him a knockout in the next round.
Recovery follows in the hospital, where Auntie’s tears and Peggy’s hopeful visit reaffirm the bond Jimmy has formed with the farm and its people. To protect those he cares about, he decides to embark on a barnstorming boxing tour, with Phlaxer acting as his manager. Peggy asks to accompany him, but he gently insists he must go alone and promises to return. A wry, almost bittersweet line from Phlaxer—“in about 10 years”—hangs in the air as he steps away.
As the train pulls away, Phlaxer makes a dramatic exit moment, leaping aboard at the last second and leaving Jimmy to pursue a future with Peggy, a choice tempered by hard-earned wisdom and a belief that redemption might be worth the risk.
> Go on. Beat it! Keep that kisser of yours off the camera. You don't photograph good. So long....Daugherty!
