Set in 50 B.C., Asterix and Obelix are living in a small but well-protected village in Gaul, where a magic potion concocted by Druids turns the townsfolk into mighty soldiers. When Roman troops carve a path through Gaul to reach the English Channel, Caesar and his aide de camp Detritus discover the secret elixir and capture the Druid leader who knows its formula, and Asterix and Obelix are sent off to rescue them.

Obelix falls for a new arrival in his home village in Gaul, but is heartbroken when her true love arrives to visit her. However, the lovers are kidnapped by Romans; Asterix and Obelix set out to rescue them on a dangerous journey that will involve gladiators, slavers and beauracracy - and a personal encounter with the Emperor himself, Julius Caesar...