The Romans having been humiliated many times by the rebel Gauls, Felonius Caucus, advisor to Centurion Nebulus Nimbus, suggests a single combat between Vitalstatistix, chief of Asterix's tribe, and the Gallo-Roman Chief, Cassius Ceramix of Linoleum. According to ancient Gaulish customs, the loser would forfeit his entire tribe to the winner. When Ceramix argues that Vitalstatistix would surely win with Getafix's magic potion of invincibility, Caucus sends a patrol to capture Getafix before the challenge is confirmed. Whilst attempting to scatter the attackers, Obelix accidentally strikes Getafix with a menhir, the impact of which causes amnesia and insanity.