January 1829: George IV is on the throne, Wellington is England's prime-minister, and snow is falling thickly on the London streets as Lieutenant-Colonel Matthew Hervey is summoned to the Horse Guards in the expectation of command of his regiment, the 6th Light Dragoons. But the benefits of long-term peace at home mean cuts in the army, and Hervey is told that the Sixth are to be reduced to a single squadron. With his long-term plans in disarray, he undertakes instead a six-month assignment as an observer with the Russian army, an undertaking at the personal request of the commander-in-chief, Lord Hill. Soon Hervey, his friend Edward Fairbrother and his faithful groom, Private Johnson, are sailing north to St Petersburg, and from there on to the Eastern Balkans, seat of the ferocious war between Russia and the Ottoman Empire. Hervey is meant to be an impartial spectator in the campaign, but soon the circumstances - and his own nature - propel him into a more active role. In the climactic Battle of Kulewtscha, in which more troops were engaged than in any battle since Waterloo, Hervey and Fairbrother find themselves in the thick of the action. For Hervey, the stakes have never been higher - or more personal.