A book of the film was released containing the story and stills from the film. It was later re-printed when Orion Publishing re-released the entire series.
In Rome, to honour the success of his campaigns of conquest, members from several provinces of the Roman Empire arrive in the city to offer gifts to Julius Caesar. Seeking to cement the celebrations with a grand show at the Colosseum, Caesar instructs the head of a prominent Gladiator School, Caius Fatuous, to ensure that the Circus Maximus is a success, promising to make him the wealthiest man in Rome, or the main attraction of the show if he fails. While discussing about the many gifts he has received from his Empire, Caius notably conceals the fact that the province containing the only village in Gaul yet to be conquered, has not sent one.
In the village at the same time, Asterix begins to notice his friend Obelix acting strangely, following the return of the chief's niece, Panacea. When Druid Getafix sees him become tongue-tied when talking with her, he reveals that Obelix has fallen in love with her. When Asterix sees that he is still infatuated with her the next day, he quickly suggests that his friend heads out for flowers to impress her. However, upon returning with a bouquet for Panacea, his heart is quickly broken when he sees her reunite with the recently returned Tragicomix, a handsome, young man whom Chief Vitalstatistix reveals will be soon marrying Panacea. Seeking to spend more time together following their reunion, the two lovers venture out into the nearby woods, but are swiftly ambushed and captured by a group of Romans, led by a fresh recruit hoping to make a good impression of himself with his Centurion, the head of a nearby garrison. However, his actions infuriate the Centurion, who berates him for his rashness before ordering the recruit to take Tragicomix and Panacea to the farthest outpost of the Empire (situated in the Sahara) before the Gauls realise what had happened. When they do, they quickly trash the camp, only to find out what the Centurion did with them, thus sending Asterix, Obelix and Dogmatix (Idéfix) to go after the pair and rescue them.
Seeking to find out where they went, the group head for the nearest Legion HQ for information, and decide to join the Roman Army to catch up with them upon learning of where they are being taken to. Although they manage to succeed in completing their training quickly and getting assigned to the same outpost, their undisciplined behaviour and their strength from the magic potion to speed up their march towards Massalia, cause them to drive their commanding officer, Dubius Status, back to Rome in tears. Unbeknown to the pair as they sail for the Saharan outpost, Tragicomix and Panacea, both of whom had been forced to do humiliating work for the outpost's men, manage to escape after a recently arrived officer tries to make a move on Panacea. However, both end up being stranded in the desert before being captured by a group of slave traders that comes across them. Sold on as slaves, the pair eventually are brought to Rome where they acquired by Caius at a slave market, who decides to use Tragicomix as part of Caesar's grand show. However, when the pair are presented to Caesar, Tragicomix refuses to bow before him during the show, while Panacea speaks out against being separated from him, leading Caesar to command that both are thrown to the lions instead for their defiance, as part of the grand finale of the Circus Maximus.
Having learnt of their escape, Asterix and Obelix desert the army and track the pair down to Rome, eventually seeking out Caius at a local bathhouse. Upon witnessing Obelix's strength when he takes down his bodyguards, Caius desperately desires them to be his new gladiators and orders his men to bring them to him. While his men easily capture Asterix, after he discovered he lost his magic potion when he separated from Obelix following a minor argument, they fail to acquire Obelix due to his invulnerable strength, who soon begins searching for his friend, losing Dogmatix in the process when he spots the misplaced magic potion and tries to get it back. That night, a storm hits the city, in which lightning causes a gutter to break and let rainwater begin flooding a cell that Asterix had been thrown into. Just before he drowns from the rising water, Obelix saves him in the nick of time. Without the magic potion and with Dogmatix missing, the pair continue their search for Panacea and Tragicomix, quickly learning that they are being held in the Colosseum to await their fate in Caesar's show.
Hoping to gain entry, the pair visit Caius' school, and manage to secure places as gladiators for the Circus Maximus, whereupon the pair soon begin to make a mess of the show, winning a chariot race, and beating down a number of gladiators. Soon the lions are unleashed, with Tragicomix and Panacea sent out into the centre of the arena without any weapons to defend themselves with. Fortunately, Dogmatix arrives with the magic potion, having recovered it from the city's sewers, and gives it to Asterix, who soon tosses it over to Tragicomix to help him deal with the lions. While attempting to capture the lions that are knocked into the air, Obelix becomes distracted by Panacea and runs into a pillar, shattering a third of Colosseum and making its audience scatter. Caesar, somewhat impressed with the show, decides to grant the Gauls their freedom.
Returning to the village, the group receive a trademark victory feast in their honour, where Asterix is thanked by Panacea for his bravery with a kiss, who is slightly surprised by her actions. As the movie ends and the villagers celebrate, Asterix sits up in a tree on his own, having somewhat fallen for her.Jack Beaber ... Asterix
Billy Kearns ... Obelix
Robert Barr ... Getafix
Gordon Heath ... Caesar
Allan Wenger ... Caius
Herbert Baskind ... Selectivemploymentax
Jerry Di Giacomo
Patrick Floersheim ... Dubious Status
Steve Gadler ... Vitalstatistix
Thomas M. Pollard
Raphaël Rodriguez ... Spanish Recruit
In 1990, the film was released on VHS by Celebrity Home Entertainment. In 2006, the film was released on Region 2 DVD as a part of a box set of animated Asterix films.