Brother and sister, they were raised in fear, told to keep to the shadows cast by the walls slowly crumbling down around them. Kai and Isak Vadra have lived their entire lives in London, scratching out a living between the walls of the city's filthy slums. While their mother struggles to keep them safe from the everyday threats of hunger and crime, a new danger presents itself, one beyond the reaches of everyday politics and police. Their mother does everything within her power to prevent this new shadow from tearing their world apart. But instead of safety, it threatens to bring to light her worst fear, that a secret their family has kept for generations will finally be revealed.