When the Romans invade Britain, one small village keeps the Roman armies at bay. But theirs is a difficult struggle so they call on Asterix and his friends for help. Asterix and Obelix are sent to Britain with a barrel of magic potion, but heir mission is fraught with peril and seems doomed when the barrel is confiscated by the Romans – until Asterix remembers he has some strange leaves in his pocket, given to him by the druid Ogamaix – leaves which will surely change the world!