In a stylized version of 1930s Chicago, a determined and square-jawed detective takes on the criminal underworld. With his iconic yellow trench coat and matching fedora, he battles against a gallery of grotesque villains controlled by the city's mob boss. The crime lord employs an army of colorful henchmen to maintain his grip on the city's rackets, but the detective is relentless in his pursuit of justice. His primary focus is on stopping the mob's operations and bringing the boss to justice, while his personal life is complicated by his relationship with his girlfriend Tess Trueheart, who wishes for a more conventional life away from the dangers of his work.

The detective's path crosses with a seductive nightclub singer with ulterior motives, further complicating his personal life and his investigation. Behind the scenes, the mob boss and his minions plot to take out the detective once and for all, setting traps and engaging in nefarious deals. The detective's dogged detective work leads him to uncover a massive scheme that could grant the crime lord even greater power within the city. As the stakes rise, the detective must navigate a treacherous landscape of deceit, betrayal, and murder, using his wits and his unshakeable moral code to maintain order in a city teetering on the edge of chaos.