Asterix the Gaul, first book of the "Asterix comic strip series" authored by Rene Goscinny and illustrated by Albert Uderzo, features Asterix, a Gaul warrior living during the Iron Age and the days of the Roman Empire.
Gaul was ruled by the Celts and included today's France, Luxembourg, Belgium, Switzerland, and some of Northern Italy. The story is set during a time when the Roman Empire had conquered all of Gaul except for Asterix's small village in Armorica, present day Brittany. The village's inability to be conquered is attributed to a potion for invincibility created by Getafix, the village druid.
The story opens with Asterix being attacked by four Romans in the woods, led by Crismus Bonus. When the Romans report having been defeated, Crismus Bonus decides to send a spy into the village to learn the secret of the Gaul's indestructibility. Caligula Minus is nominated for the task of spy after losing to the other soldiers in a game of musical chairs. He is disguised as a Gaul and led by a band of Romans through the woods chained like a prisoner. In accordance with Crismus Bonus's plans, when Asterix and his best friend and fellow warrior Obelix see who they think is an imprisoned Gaul, they immediately attack the Romans to free the prisoner, unwittingly also letting loose a spy in their village.
Once in the village, Caligula Minus immediately sees a connection between the Gauls' unsurpassed physical power and Getafix's potion and is able to trick Getafix into allowing him to sample the potion. However, during a celebratory dance, Caligula Minus's mustache is ripped off, revealing him to be a Roman spy. However, he successfully escapes and makes it back to the Roman encampment in time to demonstrate his astonishing strength.
Further adventures include Getafix being captured by the Romans, Asterix being captured when he comes to Getafix's rescue, and Getafix pretending to reveal the secret ingredients of the potion. The Romans collect and bring the "secret ingredients," including strawberries, to Getafix so he can make the potion, and Asterix tricks the Romans into believing the potion is the real one by pretending to be severely injured by a merchant's blow. When Julius Caesar arrives, he learns from Asterix and Getafix that Crismus Bonus had considered using the poison to overthrow Caesar. Caesar has Crismus Bonus exiled to Mongolia and establishes peace between the Romans and Asterix's village.