AD 42, Germany. Tough, brutal and unforgiving. That's how new recruit Cato is finding life in the Roman Second Legion. He may have contacts in high places, but he could really use a friend amongst his fellow soldiers right now.
 
Cato has been promoted above his comrades at the order of the Emperor and is deeply resented by the other men. But he quickly earns the respect of his Centurion, Macro, a battle-hardened veteran as rough and ready as Cato is quick-witted and well-educated. They are poles apart, but soon realise they have a lot to learn from one another.
 
On a campaign to Britannia - a land of utter barbarity - an enduring friendship begins. But as they undertake a special mission to thwart a conspiracy against the Emperor they rapidly find themselves in a desperate fight to survive...