After being thrust into command in a besieged fort on the Danube, ending in disaster, Alexios Aquila is disgraced but protected by a powerful uncle, and sent to the northern frontier of England to take over a force of frontier scouts, most of them members of the various tribes. They aren't an attractive prospect for a young Roman officer, but then neither is he for a tough group of soldiers with their own ways.

Alexios settles into his command, establishing good relations with the local tribe, but there are vague stirrings of trouble in the further north, and when it finally comes it is exacerbated by disastrous and tragic local events. There follows a riveting adventure narrative, one if the best war stories I've read in ages. Sutcliff does action and military personalities and men under extremes of stress exceptionally well.

Sutcliff's tendency to treat the Roman Empire as a civilising patrician force that benevolently rules the world via a kind of historical inevtibility rather than ruthelss military invaders gives her stories a Kiplingesque air, and indeed you could transport the essence of the story to some frontier of the British Empire without changing its essential personality and the cool sensible decency of the better types in the officer class. Sutcliffe's saving grace is that she can inhabit a wild celtic tribe just as thoroughly, if not more so, since she captures their distinctive voices so well. She reminds me a LOT of Mary Renault.