AD 69. Aulus Caecina Severus has thrown in his lot with the hedonistic Vitellius and prepares his legions for a gruelling march over the Alps.
Driven by the desire to repay the treachery of his former patron, the Emperor Galba, and to keep his rival Valens in check, Severus leads his army against barbarian rebellions and against the mountains themselves in his race to reach Italy first. With the vast Po valley almost in sight, news reaches the army that Galba has been killed in a coup, and that Otho has been declared Emperor by the Praetorians who he had bribed to murder their own emperor.
But there is no turning back for Severus, even if he wanted to. The Rhine legions want their man on the throne, and they won't stop until they reach Rome itself. Even once Otho is defeated, the battle for supremacy between Severus and Valens is far from over. The politics of the court and the mob is the new battleground, and Severus needs the help of his wife Salonina and his freedman Totavalas in this constant game of thrones. When stories spread of a new power in the east, Severus has to decide where his real loyalty lies: to his Emperor, to his city or to himself?