Cadwal, a widowed Celtic warrior is a dedicated father raising his children in his mountain stronghold. In these uncertain times, the tribe must be vigilant, as caught between the expanding Roman empire and power-hungry neighbours, treachery is rife.

A seasoned former general with a reputation to make emperors afraid, finds himself haunted by the threat of assassination. Unexpectedly, he is entrusted with the command of three legions stationed in the distant province of Britannia, a post that seems far removed from the treacherous politics of Rome.