Czechoslovakia, October 1937. Europe's youngest democracy is on its knees. Millions are mourning the death of the nation's founding father, the saintly Tomas Masaryk. Across the border, the Third Reich is menacing - and plotting to invade.

In the Czechoslovak heartlands, vast crowds have gathered to watch the threatened nation's most prestigious sporting contest: the Grand Pardubice steeplechase. Notoriously dangerous, the race is considered the ultimate test of manhood and fighting spirit. The Nazis, as usual, have sent their paramilitary elite: SS officers schooled to be Hitler's most ruthless enforcers. Their mission: to crush - yet again - the "subhuman Slavs". The local cavalry officers have no hope of stopping them.

But there is one other contestant: a silver-haired countess riding a little golden mare...

The story of Lata Brandisova is one of the strangest and most inspiring in all sport. Born into privilege, she spent much of her life in poverty. Modest and shy, she refused to accept the constraints society placed on her because of her gender. Instead, with quiet courage, she repeatedly achieved what others said was impossible. The scandal of her first attempt to ride in Pardubice reverberated across Europe. Ten years later, she became her nation's figurehead in its darkest hour. Then came retribution...

UNBREAKABLE is a tale of courage, heartbreak and defiance, in an age of prejudice and fear. In the background are forces - sexism, class hatred, nationalism - whose shadows darken today's world too. In the foreground are eccentric aristocrats, socialite spies, daredevil jockeys - and a race so brutal that some consider merely taking part in it a sign of insanity. At its heart is a unique hero, and a unique love affair between a woman and a horse.