This is a cute story making a lot of fun of Roman orgies and behavior. In this case a Roman governor is throwing lots and lots of orgies and is taking most of the tax money from the people and giving Rome very little. An auditor shows up and the guy poisons him. The auditor, though, knows Getafix from Asterix's village and sends for him.
Getafix has to send Asterix and Obelix up to Switzerland to get a specific flower to make a cure for the auditor. The story is then how the corrupt governor and a friend try to stop the two from finding the flower and, as usual, a lot of Romans get beaten up in the process.
The auditor is healed, he belts the corrupt governor, and has dinner with Asterix and the tribe.
