When anti-crime crusader Ward Bryant is murdered, suspicion immediately falls on racketeer Al Kruger. The murder instigates a grand jury investigation of crime syndicates like Kruger's. The investigation is to be headed by Capt. Dan McLaren, the superior officer and friend of former police detective Johnny Blake, now walking a beat in the Bronx. At one time, Kruger had asked Johnny to join his organization, but Johnny chose to remain honest. Johnny expects to join McLaren's investigation, but McLaren fires him for no apparent reason. His old friend Lee Morgan offers him a position in her numbers running game, but he gratefully turns her down. Instead, he takes Kruger up on his earlier offer. Under orders from his secret partners, Kruger wants Johnny to eliminate the weak spots in the organization. Gunman Bugs Fenner doesn't trust Johnny and, in fact, he is really working secretly for the police. His job is to discover the men behind Kruger. When the criminals accuse Johnny of being a stool pigeon, he suggests they start a new racket, based on Lee's numbers game, which is very successful. Encouraged by Fenner, Lee believes that Johnny has double crossed her. After Fenner kills Kruger during an argument, Johnny takes over. He finally meets the bosses, but now Fenner learns that Johnny is working for the police. He tricks Lee into revealing Johnny's hiding place and even though she has a change of heart and tries to warn him, Fenner and Johnny shoot it out. Fenner dies and Johnny is badly wounded, but he manages to finger the bosses before he dies himself.