AfterthecorruptformerMayoriskilledbythepeasants,poorjanitorJuanVargasisappointednewMayorofadeserttownincentralMexico.Althoughhetriestobringthemottooftherulingpartytotown(modernity,peaceandprogress)herealizessoonthatthere'snothingtodoagainstcorruption...excepttobecomecorrupt.Stepbystep,helpedbyhispistol,JuanVargasbecomesthelawandtheworstMajorinthetown'shistory. 故事讲述墨西哥农民杀死腐败的前市长后，不幸的看门人阿瓦尔加斯在墨西哥中部被任命为一个沙漠镇的新市长，他努力提倡执政党的新意识，到任不久就立下反对腐败的座右铭，但反对也开始变得腐败，一步步在他的枪手帮助下，阿瓦尔加斯成为法郎和镇上历史最恶劣的一页。
