In 1932, Tintin, a reporter for Le Petit Vingtième, goes with his dog Snowy on an assignment to Chicago, Illinois, to fight against the city's organised crime syndicate. Soon after arriving there, Tintin and Snowy are kidnapped by gangsters and brought before mobster boss Al Capone, whose criminal enterprises in the Congo were previously thwarted by Tintin. With Snowy's help, Tintin subdues his captors, but as he goes to inform the police, they reject his claims, and the gangsters escape while Tintin is away. After surviving attempts on his life, Tintin meets Capone's rival Bobby Smiles, who heads the Gangsters' Syndicate of Chicago. Tintin is unpersuaded by Smiles' attempt to hire him, and after Tintin orchestrates the arrest of his gang, Smiles escapes and heads west.[1]

Tintin en Amérique reste un chef d'oeuvre dans la saga d'Hergé, portant un regard "pas si gentil" sur les Etats Unis d'Amérique. On y trouve la police de Chicago à la solde du bandit Al Capone, et les "peaux rouges" y sont décimés et expulsés sans ambages. Bien sur, le "modèle Belge" triomphe comme il l'avait déjà fait dans Tintin au Congo, Le Lotus Bleu et Les Cigares du Pharaon.