Asterix and Obelix, warriors of the last village in Gaul still free after the Roman invasion...
Julius Caesar has invaded Britain and succeeded, mainly because the British soldiers under Cassivelaunos stop fighting every day to drink hot water (with a drop of milk), and refuse to fight over the weekend. As with Gaul, a single village remains independent, defying the Romans. One member of the village, Anticlimax, is dispatched to Gaul to enlist the help of Getafix the druid in providing magic potion for the British rebels. It is decided that Asterix and Obelix should accompany him back to his village to help transport a whole barrel full of the potion.
In Britain, the barrel of potion is confiscated from a pub cellar along with all the "warm beer" (bitter) by the Romans, who set about tasting all the barrels to find the right one. Asterix and Obelix steal back all the barrels but Obelix gets drunk and starts a fight. During the fracas, a thief steals the cart with all the barrels. After a brief stay in the Tower of London the three heroes hunt down the potion, which is being used as a pick-me-up for a Rugby team. Eventually the potion is lost in the Thames after an attack from a Roman catapult.
Finally reaching the independent village, Asterix eases the Britons' disappointment by claiming he carries herbs to remake the potion; these are later revealed to be tea. With a psychological boost, the village prevails against the Romans. Asterix and Obelix return home to the inevitable feast. The Britons like the tea so much, they proclaim it shall be their national drink
Jules César débarque en Angleterre, où un petit village résiste encore aux légions romaines. Mais la situation est grave et le chef Zebigboss, envoie chercher de l'aide au village d'Astérix et D'Obélix, qui traversent la Manche pour leur prêter main forte...