After Obelix single-handedly defeats a new regiment of Romans sent to Totorum (as part of a surprise birthday gift from the other villagers), Caesar is once again pondering what to do with the Gaulish village. A young economist named Preposterus comes up with a novel solution: by introducing "the profit motive" (i.e. capitalism) into the village, he hopes to make the Gauls decadent and complacent enough to avoid causing any trouble, citing Caesar's formerly brilliant but now lazy and fat generals as proof of the effects of wealth. Preposterus then moves to Totorum and spots Obelix in the forest carrying a menhir. Preposterus offers to buy all menhirs Obelix can make, claiming that the richest man in the village is also the most influential.

As time goes on, Preposterus keeps increasing the money he gives Obelix as well as convincing him to produce more menhirs, which leads him to start hiring people to help make them as well as to hunt boars to feed them. Obelix's new workload causes him to neglect Dogmatix and Asterix. The latter tries to teach Obelix a lesson by convincing other villagers like Unhygienix and Fulliautomatix to start their own menhir companies. Pretty soon, exactly half the village is producing menhirs while the rest is hunting boars to feed the other half. The only people not caught up in this are Vitalstatistix, Getafix and Asterix, with the latter believing that this will all blow over soon.

Meanwhile back in Rome, Caesar's treasury is being drained and he's stuck with a bunch of menhirs. Preposterus suggests selling them to wealthy Romans, marketing them as symbols of wealth and rank. The business becomes a huge success until a Roman businessman starts undercutting the market by making cheaper Roman menhirs. Caesar tries to ban the sale of the latter with no success and soon, the Phoenicians and Egyptians start producing their own menhirs, eventually crashing the market and making them all worthless. Caesar then orders Preposterus to return to Gaul and stop buying the Gaulish menhirs or be thrown to the lions.

Back in Gaul, Obelix is starting to get tired of his life as a businessman and wants things to go back to the way they were. He reconciles with Asterix and they go hunting like they used to. Meanwhile, Preposterus no longer buying the menhirs has naturally angered the rest of the villagers. Despite originally blaming Obelix, they then blame the Romans and do their thing. With the sestertius having been massively devalued back in Rome thanks to the whole mess, everyone is broke and everything goes back to normal in the village.
* YouFailEconomicsForever: Brillantly subverted. Even if (or because?) it's a parody, ''Obelix and Co.'' is remarkably accurate and panels or even whole pages are frequently used in French middle and high school textbooks.
* BreakTheHaughty: Centurion Ignoramus and his men are some of Caesar's best soldiers, and they know it. After their arrival in Totorum, Ignoramus rallies his legionaries with a confident speech about how they will be the ones to finally overrun the Gaulish village. One single-handed, resounding defeat by Obelix (with a bit of help from Dogmatix) later, and they give up completely and start spending their days lounging about the camp, trying to keep as low a profile as possible while waiting for their relief to show up. Caesar is nearly apoplectic with rage when he learns his crack troops were demoralised to the point of uselessness in a single day by a single Gaul.
* ConspicuousConsumption / ImpossiblyTackyClothes: At the suggestion of Preposterus, Obelix gets some "smarter clothes". Said clothes turn out to be hideously garish. Once the rest of the village is caught up in the craze, all the other menhir entrepreneurs start wearing these hideous clothes as well.
** Preposterous markets the menhirs as status symbols since they have no other use. In the page where this happens, the narration box warns the reader that this segment might be hard to understand since [[SarcasmMode in modern times, no one would dream of selling something completely useless.]]
* CreatorCameo: As the first Totorum garrison marches out of the camp, the two legionaries carrying the overweight drunk on a shield are René Goscinny and Albert Uderzo. The overweight drunk, meanwhile, is [[ShoutOut a caricature of their friend Pierre Tchernia]], whose likeness appears in many ''Asterix'' books.
* InsaneTrollLogic: Roman menhir seller Meretricius claims that he can't stop producing menhirs since it would endanger the jobs of hundreds of workers. Once Caesar points out that said "workers" are ''slaves'', he claims "Exactly! The right to work is the only right a slave has. He must not be deprived of it!"
* OOCIsSeriousBusiness: When the rest of the villagers are trying to keep Obelix' birthday gift a secret, Fulliautomatix tells Unhygienix that the new garrison at Totorum are freshly arrived that day. Obelix only hears part of the conversation, and asks what has arrived fresh that day; Fulliautomatix covers by sneering, "Well, not these fish, anyway!"... and Unhygienix simply chuckles to himself, leading Obelix to deduce that they're hiding something. He even {{Lampshade|Hanging}}s their strange behaviour to Asterix immediately afterward (only for Asterix to chuckle to himself).
* RunningGag:
** A character will use economical terms, causing the person he's speaking to to answer "Eh?" in a baffled fashion. The first character will then restate his argument using YouNoTakeCandle speech. Happens notably between Preposterus and Obélix, Obélix and Astérix (with Obélix completely mashing up the economical terms), Preposterus and ''Caesar'', and Getafix and Astérix.
** Whenever a visitor arrives at Totorum, he is announced to the rest of the camp by the lookout. In his first appearance, he is every inch a soldier, his uniform, posture, and diction pristine (when Asterix arrives to bait the garrison into attacking for Obelix' birthday, the lookout declares, "There's a Gaul at the camp gates, Centurion, sir!"). After the Totorum garrison stop caring about professionalism, the lookout becomes increasingly lazy and dishevelled each time we see him; he ends up with waist-length hair, is often seen slouching or relaxing in a hammock, and at one point tells the camp a visitor is arriving by simply whistling to them.
* ShoutOut: A pair of Roman Legionaries who heavily resemble LaurelAndHardy.
* TakeThat: Believe it or not, Preposterus is a satire of Jacques Chirac. Yes, THAT [[ Jacques Chirac]], during his first tenure as France's Prime Minister (1974-1976). Through him, it's also a satire of ''[[ énarques]]'' and technocracy in general.