Lucius disappoints his father by becoming physician. After his first surgical procedure, he learns he must join the legion to watch over his younger brother, Marcus. Ever since their oldest brother was killed in battle, Marcus has been eager to take his turn killing barbarians for the glory of the Republic. Aia, a tempestuous young Druid priestess fights with her mother over her warrior lover. Their ambitious chieftain wants the tribe to move to Gaul with the Helvetians. For incentive, he disrupts the Imbolc ceremony and burns down the village. As Caesar's legions chase the barbarians through Gaul, Lucius learns traditional surgery from a crusty old surgeon on his last campaign. Marcus, now an infantry trainee gets into trouble with a fellow legionnaire who is hiding in the military after a deal in the "family business" went bad. After the Roman Army's first major battle, Lucius discovers Aia searching his surgical area for supplies. He is forced to make a quick decision which will change their lives forever. Romans are considered civilized, Helvetians and Gauls barbarians, but as these ancient cultures clash, their differences are blurred and their actions surprise.