The film involves a handpicked group of expert soldiers who infiltrate the enemy's stronghold to locate and destroy a secret weapon prior to the Battle of Alesia.

Centurion Claudius Marcellus leads three other men, Germanicus the strong man, Varus an expert knife thrower and Castor an experienced and highly competent soldier.

Joining the four commandoes is young Valerius; a boy who ran away from a wealthy Roman home to become a Legionary but only became a Gunga Din type labourer.

Livilla and Valerius have no experience whatsoever, and Drusus is an unknown asset; he has lost all desire to be a Roman soldier and only wishes to return home rather than participate in a suicide mission but during their escape he proves himself highly proficient with a captured bow and quiver of arrows against the enemy.

The group faces further tribulations when Valerius is captured and tortured by the enemy to reveal the mission, location and composition of the party as well as the plans of the main body of Caesar's troops.