The Trials of Koli by MR Carey

Beyond the walls of Koli’s small village lies a fearsome landscape filled with choker trees, vicious beasts and shunned men. As an exile, Koli’s been forced to journey out into this mysterious, hostile world. But he heard a story, once. A story about lost London, and the mysterious tech of the Old Times that may still be there. If Koli can find it, there may still be a way for him to redeem himself – by saving what’s left of humankind.