Lucky Luke arrives at Fort Smith by playing Bart, a terrible looter of diligences. he must be judged by William Story, a judge to say the least very corrupt. At the time of sentencing, a elegantly dressed woman makes a very noticed entrance into the court. It is Belle Starr, nicknamed "The Bandit Queen", an inescapable personality in the area which, alas, can be said to be the only real authority. One fact is certain, honest people bother him. So she gathers in her ranch many bandits on the run who, too happy to escape justice, put themselves at her service by agreeing to share their loot. The sheriff is desperate. Every time he arrestes a bandit and this one is tried, Belle Starr makes him free by paying bail. Lucky Luke then decides to rise to the challenge. Since the only solution to meet Belle Starr is to be a bandit, it will be enough for the sheriff to indict Lucky Luke and make him judge. Of course, there will be no trial, but with some dollars to accept the case.