As a unique gift for Caesar, Odius Asparagus, prefect of Gaul, decides to bring him one of the indomitable ones from the village surrounded by fortified camps. As the only Gaul the local Legionaries are comfortable with going up against, Cacofonix is kidnapped. Never ones to let a fellow Gaul be put in danger, Asterix and Obelix head for Rome on a Phoenician merchant's ship, thrashing a pirate crew along the way.
In Rome, Caesar's lanista (trainer of gladiators) Caius Fatuous decides that Cacofonix is no good as a gladiator, but will make excellent food for the lions. Asterix and Obelix learn of this, and because they don't know where Cacofonix is being held, decide to join the games themselves. Needless to say, they handle their formal training a bit differently than most would-be gladiators.
Sure enough, at the next games, the antics of the Gauls drive Caesar into frustration. However, the crowd eats it up, so Caesar permits the Gauls to name their reward; they chose to go free, as well as bring Caius Fatuous with them. Caesar is more than happy to let them have the unwitting instigator of his recent humilation. The Gauls put Caius to work on the Phoenicians' ship, showing him what it's like when someone lives off of your muscle. The Gauls return to their village, have their feast...
...and Cacofonix ''still'' gets BoundAndGagged.
(Note: First appearence of the Pirates)
* AnimatedAdaptation: Combined with ''Asterix the Legionary'' to create ''Asterix vs Caesar''. Instead of Cacofonix, Tragicomix and Panacea, the romantic subplot leads from ''Asterix the Legionary'', are captured, so Asterix and Obelix pursue them by first joining the Roman Legion, then heading to Rome to become gladiators.
* BeenThereShapedHistory: In the arena scene in the AnimatedAdaptation, Obelix gets distracted and accidentally runs into a support pillar and causes a sizable portion of the Colosseum to collapse. [[ArtisticLicenseHistory Quite an impressive feat when you remember that the Colosseum wouldn't even be built for another century.]]
* BrownNote: This is where Cacofonix's bad voice is fully illustrated.
* GoneHorriblyRight: Caius Fatuous involves the Gauls because he thinks they'll make the games more interesting.
* NonActionGuy: Cacofonix's role as this is what gets him captured.
-->'''Gladiators''': Ave Caesar! Those who are about to die salute you!
-->'''Asterix and Obelix''': Hiya, Julie! How ya doing?[[note]] In the British edition of the book, they use the much more British "Hello, Julius old chap!"[[/note]]