Hairpin Harry Dutton is paroled from prison after ten years. He discovers that his wife Polly has divorced him and married Big Mike McCafferty, the detective who sent Harry to prison. Polly fears Harry may exact revenge on her for her perfidy and arranges for her new husband to frame Harry.

Convict Hairpin Harry Dutton is in solitary confinement because of a fight he had with another prisoner over an insinuation that Harry's wife Polly, the Poppy Girl, had double-crossed him and been unfaithful during his ten-year jail stay. After his parole, Harry's dreams are shattered when he learns from his friend Boston Blackie that Polly has divorced him and married Big Mike McCafferty, the detective responsible for Harry's conviction. Harry seeks revenge. He finds his son Donald and plays games with him without revealing his true identity. Harry learns that Polly and McCafferty are planning to frame him again. He goes to the McCafferty home with the intention to brand Polly's cheek, but Donald's crying causes him to desist. Harry runs away with Donald and finds contentment with his son in the mountains.