Rome, AD 63. Vespasian has been made Governor of Africa. Nero, Rome's increasingly unpredictable Emperor, orders him to journey with his most trusted men to a far-flung empire in Africa to free 500 Roman citizens who have been enslaved by a desert kingdom. Vespasian arrives at the city to negotiate their emancipation, hoping to return to Rome a hero and find himself back in favour with Nero.

But when Vespasian reaches the city, he discovers a slave population on the edge of revolt. With no army to keep the population in check, it isn't long before tensions spill over into bloody chaos. Vespasian must escape the city with all 500 Roman citizens and make their way across a barren desert, battling thirst and exhaustion, with a hoard of rebels at their backs. It's a desperate race for survival, with twists and turns aplenty.

Meanwhile, back in Rome, Nero's extravagance goes unchecked. All of Rome's elite fear for their lives as Nero's closest allies run amok. Can anyone stop the Emperor before Rome devours itself? And if Nero is to be toppled, who will be the one to put his head in the lion's mouth?