77AD Gaius Valerius Verrens is an honoured member of the Emperor Vespasian’s inner circle, but the continuing enmity of the Emperor’s son Domitian means that, even in Rome, danger is never far away. Meanwhile, in Britannia, the governor, Gnaeus Julius Agricola prepares to carry out Vespasian’s order to take his legions north and subdue the entire province.

When Valerius is appointed legatus iuridicus, Agricola’s chief legal adviser and deputy governor, it seems the perfect opportunity to take his wife and son out of reach of Domitian’s wrath. But Valerius swiftly discovers that in Britannia the ghosts of the past are never far away and he has enemies more dangerous by far than Domitian.

The massacre of a Roman garrison and suspicious death of the legate of the Ninth Legion throw Agricola’s preparations into confusion. Now his eyes turn west to Mona, the Druids Isle, where the Celtic priesthood still harbours hopes of ridding Britannia of Roman rule. But to deal with the druids and their savage Ordovice protectors Agricola needs a soldier he can trust at the head of the ‘unlucky’ Ninth. Only one man in the province has the experience and ability to meet the challenges ahead.

So Valerius must lay down his scrolls and pick up his sword again to march beside the eagle of the Ninth. It’s only as he stands on the shore opposite Mona that he understands any glory his new legion wins is likely to be fleeting and tainted – and that he has placed his family in deadly peril.