In a California city, Lt. Fred Parks interrogates baker Albert Willis about his possible connection to the recent eastside robberies. After repeatedly stating that he is innocent, Willis finally erupts in anger and punches Parks, who hits him back. Chief Joseph E. Conroy enters just in time to hear Willis threaten revenge, but is compelled to release him after he reads that councilman Edgar Goodwin is calling for an investigation of police brutality. Willis returns to his wife Helen, but slips out again that night, and hours later, Parks is found shot. Joe takes on the case, and immediately suspects Willis, but has only bullets as evidence. When the police try again to arrest Willis, the baker runs away, falling on his head during the chase. Again, he swears he is innocent, and after his lawyer, wife and Goodwin hear about Willis' head injuries, they put pressure on Joe. Joe is forced to let Willis go, but instructs an officer to follow him. That evening, however, the baker slips into a church and disappears. Hours later, two more officers are killed, and this time Joe arrests Willis himself. When Willis provokes another fight, however, the altercation is witnessed by a reporter, and Joe is soon fired for brutality and labelled unbalanced. Undaunted, he asks his friend, private detective Matt Matthews, to help tail Willis. Over the next days, Willis grows more disturbed by the shadows following him, finally telling Helen that he must leave town to clear his head. He heads to Mexico's Border City, with Joe close behind, and there watches his girl friend Marianna sing at a bar. Marianna knows nothing of Willis' other life, and accepts his rough treatment because she loves him deeply. That night, Joe shows Willis' photo around town, and is duped by a shyster, who stabs and robs him and leaves him for dead. The next morning, young Mexican boy Petey finds Joe and, along with his uncle Charlie, minister to him in their apartment. Marianna, who lives upstairs from Petey, helps them, pocketing Joe's photo of Willis, which is captioned with the question "Killer or family man?" Later, at Willis' party, Marianna asks him to marry her, but he refuses, promising only to keep returning. Marianna is then horrified to witness Willis throwing a clumsy waiter over an indoor balcony. She heads for home, followed by Willis, and while Joe watches from the window, Willis grabs her roughly and threatens her. Marianna runs inside, where she attempts to extract information out of Joe by kissing him. He tells her nothing, however, and in retaliation, she puts sleeping powder in his coffee. When she leaves, Joe follows, not realizing he has been drugged. He hides in the alley behind the bar, where he hears Willis threaten Marianna once again, and attracts Willis' attention briefly when he stumbles as he leaves. In the morning, Joe readies to go, stopping only to say goodbye to Marianna, who tells him quietly that she has made a big mistake. Meanwhile, Willis begins to believe that the "drunk" in the alley is Marianna's new lover, and jealously storms into her dressing room. When she admits she knows he is married, Willis realizes the drunk was Joe and beats up Marianna. She runs to Joe's hotel room to warn him, and, seeing her bruises, Joe explains that he must prove Willis guilty in order to clear his own reputation. He shows her a telegram that reveals Willis' participation in a local hijacking ring. When Joe steps outside to bring the telegram to the police, Willis and his goons ambush them and bring them to the bar. Willis first tries to force Marianna to kiss Joe, then plans with his goons to create a ruckus and kill them. Joe, meanwhile, learns from Marianna that Willis never attends church, and deduces that Willis must have entered church only to hide the gun. Just then, the goons start a fight and the bar erupts in confusion, allowing Joe and Marianna to race out the back door. Willis follows, and in the back alley, Joe punches him and drags him into his car. The goons see the car and report the "kidnapping" to the police, who take off after Joe. In order to return to California to find the gun that will prove Willis' culpability, Joe and Marianna force Willis into the back of a truck, but as soon as they reach Joe's hometown, Willis hops off. Knowing he will run to the church, Joe tries to follow him, but is arrested along the way. Marianna goes to the church, where Willis has retrieved his gun and now takes Marianna hostage. When Joe then bursts in with the policemen, Willis drags Marianna onto the rooftop. A chase ensues, during which Willis shoots Marianna before Joe can break through the door and kill Willis, who falls to the ground. Joe takes Marianna in his arms, and she whispers that they should have met sooner. He then carries her dead body downstairs to the ambulance, and walks alone down the dark city street.