AD 60. Britannia is in turmoil. The rebel leader Boudica has tasted victory, against a force of tough veterans in Camulodunum.

Alerted to the rapidly spreading uprising, Governor Suetonius leads his army towards endangered Londinium with a mounted escort, led by Prefect Cato. Soon it's terrifyingly clear that Britannia is slipping into chaos and panic, with ever more tribal warriors swelling Boudica's ranks. And Cato and Suetonius are grimly aware that little preparation has been made to withstand a full-scale rebellion.

In Londinium there is devastating news. Centurion Macro is amongst those unaccounted for after the massacre at Camulodunum. Has Cato's comrade and friend made his last stand?

Facing disaster, Cato prepares his next move. Dare he hope that Macro - battle-scarred and fearless - has escaped the bloodthirsty rebels? For there is only one man Cato trusts by his side as he faces the military campaign of his life. And the future of the Empire in Britannia hangs in the balance.