The title alludes to Julius Caesar's classic book, Commentarii de Bello Gallico (Commentaries on the Gallic War). The comic tells a slightly different version by adding a fictitious Chapter 24 (XXIV) named "Defeats at the Hands of the Indomitable Gauls of Armorica". Caesar's publisher, Libellus Blockbustus, deletes this chapter, since it would spoil the Roman leader's curriculum vitae. A mute Numidian scribe, Bigdhata, steals a copy of the chapter and gives it to the journalist Confoundtheirpolitix, who in turn passes it on to the village of indomitable Gauls.
Chief Vitalstatistix is unfazed by the lie that all Gaul has been conquered by the Romans, but his wife Impedimenta urges him to campaign for the truth. Since the Gauls have, unlike the Greeks and Romans, no skills in reading and writing, the druid Getafix accompanied by Asterix, Obelix and Dogmatix travels to the forest of the Carnutes to meet his former teacher, Archaeopterix, who shall then pass on the truth by word of mouth to future generations. The true story eventually reaches René Goscinny and Albert Uderzo in a French cafe, who publish it and thus the mystery behind all the Asterix stories is finally unveiled.