Phillip Davidson (John Mills) is released from prison after serving twelve years for a murder he didn’t commit. He holes up in a bleak, remote shack on the Marshes, where he plots his revenge against those who lied at his trial. (A flashback provides us the details: a smuggling job goes sour, and Davidson is blamed for the death of a man who, in fact, is not dead. His girlfriend, Fay—who, in one of the film’s neat little ironies, subsequently marries a police superintendent)—is coerced by her father to lie about the identity of the man who was burned in the boat fire that followed the altercation).

As he slowly formulates his plan for revenge, Davidson frequents a rundown tavern on the Marsh, where he tries to get a line on the punch-drunk boxer who also lied at his trial. There he gets involved with Ilse (Norwegian actress Eva Bergh), a refugee with the type of intense emotional antennae that allows her to recognize a latent spiritual side to Davidson. He saves her from being raped one night, and a simultaneously awkward and touching relationship begins to develop, forcing Davidson to re-evaluate his need for revenge.

Meanwhile, Fay (Ellzabeth Sellars) and her husband (John McCullum) are extremely worried. Her lies—and the really dangerous secret that the man presumed dead (Boyd, played with nicely escalating desperation by John Chandos) is still a presence in the underworld—are in danger of exposure. When Davidson intimidates the fighter into recanting his earlier testimony, Fay is forced to find Boyd and arrange for her own disappearance—sacrificing her suburban home with husband and son.

Before she can finalize those arrangements, however, Davidson confronts her. Taking a cue from his developing attachment to Ilse, he backs away from revenge, explaining to Fay how he had shed his desire to punish her for what she’d done to him.

Boyd, however, doesn’t turn up to help Fay, and his path crosses Davidson’s when the barkeeper enlists him to deliver a package to Boyd’s office. Fay’s husband, aware of her lie from even before their marriage, tracks his wife down and finds out that Boyd is alive. He figures out that Boyd and Davidson are now in a death chase across the Marsh, and he gives chase, hoping to intercept the two men before Davidson is killed.