The story kicks off when a Roman senator, Lactus Bifidus, organizes a massive chariot race across the Italian peninsula to prove the superiority of Roman roads. To ensure a Roman victory and please Julius Caesar, the race is open to everyone in the "known world"—but Caesar insists a Roman must win.

: Fittingly, his faithful co-pilot is named Bacillus (Latin for "bacteria").

Enter our heroes. After a sibyl predicts Obelix will become a champion charioteer, he buys a sports chariot and drags Asterix and Dogmatix along for a high-speed tour of Italy. The race isn't just about speed; it's a culinary and cultural tour, featuring everything from Parma's ham to the volcanic dangers of Pompeii.