Caesar is exasperated by this village of Armorica which continues to ridicule the powerful Rome. The chief of his secret police will then propose to him to introduce a druid spy in order to obtain the recipe of the magic potion. This mission is entrusted to Zerozerosix, a aspiring-druid who has systematically failed the examination and who wants to revenge. An unforeseen circumstance will allow Zerozerosix to infiltrate. Panoramix has no more oil (rock oil) to prepare his magic potion! To obtain it, Asterix and Obelix go to Mesopotamia, accompanied by Zerozerosix to whom Panoramix promised the recipe could no longer make the potion. However, he will do everything to ensure that the expedition fails.