There's a bit of an overall story here as Tintin takes on a succession of American gangsters, now being internationally renowned as "world reporter number one" who is specifically setting out to clean up the mobs which may have been a good booster when the story was originally told in Le Petit Vingtième but now just sounds utterly ridiculous. The result is that from the moment of his arrival he comes under attack by a succession of mobs. However, there isn't the greatest amount of structure to this. Rather than having Tintin steadily work his way through ever higher tiers of gangsters, the story instead throws out a random succession of foes, starting with Al Capone. Whether the real Capone knew about his portrayal is unknown, but it's a rather unsatisfactory appearance as he gets captured by Tintin only for the police to disbelieve him and the gangster then disappears from the story altogether.
Subsequently the bulk of the story involves Tintin's pursuit of Bobby Smiles, head of the Gangsters' Syndicate of Chicago and rival to Capone. But then after Smiles is captured the story shifts first to another, unnamed, syndicate with another escaping boss who is subsequently pursued and captured, then finally to a group first called the "Distressed Gangsters Association" and then later reported as the "Central Syndicate of Chicago Gangsters". Though the idea of multiple crime syndicates operating in the same city is believable, there's only a limited attempt to tie them together beyond Smiles offering Tintin money to take out Capone (who completely disappears from the narrative at this point) and a comment that Smiles and the currently unnamed "Bugsy Kidnap" are executives of the DGA. But it doesn't really hang together well, with no attempt by Tintin to play off the gangsters against each other. Instead it's the one thing after another approach, with only a bit of lip service to joint ties.
It's hard not to guess that this tale is the product of a writer and editor pushing in two entirely different directions. One seems to want to tell an exciting adventure of a young reporter single-handedly taking down the mobs. The other seems far more interested in the American frontier and capitalism, trying to make points about the United States. This story was originally serialised in Le Petit Vingtième, the children's supplement of the Le Vingtième Siècle, but to call the parent newspaper "conservative" or "right-wing" can deeply mislead an English language audience. Right-wing politics have evolved differently in continental Europe compared to much of the English-speaking world with different perspectives on capitalism and the United States. The portrayal of the States is replete with the clichés of the frontier and the big cities, often feeling like a soulless environment in which authority is weak and mispurposed. Whether it's the Chicago police who seem absolutely useless to the point of being counter-productive or the rural sheriff too busy getting drunk to free an innocent prisoner about to be lynched, the effect is a dark land that isn't at all glamorous or ordered.
The sequence that Hergé seems to have been most interested in is the one with the Native Americans, as shown most obviously by just about every single cover used for the album depicting Tintin out in the Wild West. But despite the events of a single page this is not a great portrayal. The Blackfeet tribe are shown as violent, gullible, easily manipulated and succumb to virtually all the traditional clichés of a hostile group that attack the hero. It's easy to see why this part of the story has caused discomfort and was left out of the 1990s cartoon adaptation (which also left this one to the last of the twenty-one "regular" albums that were adapted). But then comes probably the most famous sequence of the story on page 29. Whilst escaping from a cave with a boulder over the entrance, Tintin inadvertently strikes oil. Suddenly men rush up to him and offer huge amounts of money (for the time) up to $100,000 for the oil well. When he says that the land belongs to the Native Americans, the businessmen instead offer the tribe a mere $25 and half an hour to leave the land, then getting the national guard to drive them out at gunpoint. In no time at all a city is built.
The Blackfeet are not seen again in the story, making their plight seem almost incidental. But it's a striking moment of sympathy for an indigenous people driven out for economic interests. And it appears to be making a point that can sometimes get lost due to particular albums being absent from releases. The clear unspoken comparison is with the portrayal of the Belgians and the Congolese in the previous book, Tintin in the Congo, as though the Belgian paternalist approach to indigenous peoples is superior to the American displacement approach. There's no overt commentary on this, with Tintin and Snowy next seen in the new city, but it makes more sense as an assertion of what is wrong with the US, and implicitly how Belgium is better, than as cry for sympathy for a people who have been given a distinctly unsympathetic portrayal.
The aforementioned city is constructed at a rapid pace, to the point that the next day Tintin gets told off for still wearing his frontier attire. Later on, there's a scene at a factory where scrap cars are turned into tin cans and vice versa, whilst a single machine performs all the stages of meat production from slaughtering to tinning. Just to add to the horror, dogs, cats and rats are used to make salami but a cut in the price paid for them leads to a strike. Once again, it's a portrayal of American capitalism as a nasty soulless force that is not to be emulated. Elsewhere there's fakery aplenty, whether a detective who talks amazingly but proves to be utterly incompetent or even a circus strongman who actually lifts fake wooden weights. Time and again the portrayal of the country is completely cynical and a rejoinder to those in Europe who saw the United States as a land of great hope to potentially escape to.
Tintin and Snowy are the sole heroes of the story, the latter continuing to pass comment and on one occasion is still understood by Tintin, a feature that was now dropping away. Otherwise we have a tale of our hero going to a land where things have gone wrong and the authorities have failed but the hero puts things to right, a story trope commonly told in the west but rarely with the United States as the victim to be rescued. This is a somewhat rambling tale that's trying to meet multiple demands and fill in the time by replacing the adversaries, but it manages to makes its statements as well.