A new age has dawned for Rome. Following the brief reign of Emperor Nerva, Marcus Ulpius Trajan inherits the mantle of Caesar. A revered general and statesman, the senate a people of Rome greet his rise with an optimism not seen since the reign of Vespasian.
Tiberius Artorius Castus, whose tenure with the Vigiles of Rome is ending, is summoned by Trajan to the Rhine. The emperor offers him a return to active service with the newly raised Equites Singulares Augusti, more commonly known as the Imperial Horse Guards.
Rome eagerly awaits the arrival of its new, charismatic Caesar, yet Trajan must first secure the Rhine and Danube frontiers. He musters a division for an expedition against the Marcomanni in retribution for their invasion in support of the Pannonia Revolt, six years prior. For Tiberius, the campaign offers a chance at redemption, as the Imperial Horse Guards accompany Trajan across the Danube, into the land of his endless nightmares.