The novel begins with tribune Marcus Scaurus leading three cohorts of one of Julius Caesar's legions in Gaul on a "reconnaissance in force" when they are confronted by a Gaulish force twice their size led by Viridovix. The initial fight was hard but the superior numbers of the Gauls left the Romans surrounded. Viridovix fought his way through the Roman defensive ring and confronted Scaurus. By unvoiced consent, both sides paused to watch their leaders fight a duel. Viridovix carried a druid's sword and was surprised to see Scaurus had one too as spoils of war. As the two blades neared for their first blow, they began to glow and a bright golden dome covered the Roman circle when they touched along with the clap of thunder. The Romans (and one obstreperous Celt) were transported to an unkno