Detritus decides to capture the potion for himself, and hearing that the clever Asterix and permanently invincible Obelix are the backbone of the Gaulish forces, attempts and fails to eliminate them.

The "soothsayer" later drugs and hypnotises Asterix to create a diversion while he recaptures the tax money; but news of the theft reaches Caesar, who comes to the garrison himself, demanding the legion attack.

Asterix joins Getafix in the dungeon, where the pair resist Detritus' demands to make the magic potion, until he tortures Idefix (Dogmatix).

Detritus uses the potion to throw Caesar into a cell (locked in an iron mask), and takes command with an oblivious Obelix as his bodyguard.

[1] An action video game based on the film, developed by Tek 5 and published by Cryo Interactive, was released for the PlayStation and the PC.