The story focuses on Asterix and Obelix heading to Rome to rescue their village's bard, Cacofonix, which culminates in them having to infiltrate the gladiatorial games in order to save his life.

There, he informs Centurion Gracchus Armisurplus, the camp's commander, that he intends to gift Julius Caesar with one of the Gauls from the village that resists Roman rule.

Upon arriving in Rome, the pair visit a restaurant owned by a Gaulish chef named Instantmix, who offers to help them find Cacofonix, but request they discuss the matter privately at his home in the evening.

To pass the time, Asterix and Obelix visit the public baths of the city, where they unknowingly catch the interest of Caius Fatuous, a prominent gladiator trainer, who considers them perfect candidates for the upcoming games at the Circus Maximus.

When evening arrives, the pair meet with Instantmix, who reveals to them that Cacofonix was imprisoned in the Circus and is set to be fed to the lions in the games - Caesar having decreed this after Asparagus presented the bard to him, who was then examined by Fatuous over his fighting skills.

On the eve of the games, after having Fatuous give them a guided tour of Rome, Asterix and Obelix visit Cacofonix in his cell, informing him of their plan to free both him and the gladiators they met.