It is the bitterly cold winter of 1944/45. The Red Army is advancing on Eastern Prussia, the easternmost province of Germany, at the start of its inexorable advance towards Berlin. Millions of East Prussians are desperate to flee, but the Nazis order them to stay and fight. Finally, with the Russian guns in earshot, they are allowed to leave. They soon realise that they are surrounded, cut off from the rest of Germany. Many of them take the perilous route over a frozen lagoon, the only route left open. With them are thousands of the most superb horses in the world, the Trakehner, bred over the past two centuries in East Prussia. They flee in large herds or are harnessed to waggons or sleighs and face the same dangers as their guardians and owners. With little to eat, the target of Soviet bombers and tanks, many of them die on the way. Only a few hundred reached the West. They had saved their owners, and their owners had saved them – rarely has there been such a bond between men and horses. But the story is not over. Given the harsh conditions, the hunger, deprivation and poverty of the immediate post-war years, can the breed be built up again?