Asterix The Legionary by Rene Goscinny

When a young friend from their Gaulish village enlists in the Roman legion to pursue his romantic interest, two loyal villagers set off to find him. They secretly join the army, endure absurd training and military life, are shipped to foreign postings, and confront a series of comic obstacles—from rigid centurions to desert postings—using guile, the druid's magic potion, and sheer brawn to locate and rescue their companion, outwit the Romans, and return home to jubilant celebration.