An audacious and terrifying new thriller from the author of the international bestseller The Genesis Secret. When David Martinez receives an ancient map from his dying grandfather, he is led into the heart of the Basque mountains, where a genetic curse lies buried- and a frightening secret about the Western world is hidden. Meanwhile, London journalist Simon Quinn is investigating two violent murders. Both victims had once been interned in a top-secret Nazi camp-and both came from the Basque region. With The Marks of Cain, Tom Knox delivers on the promise of his astonishing debut novel, crafting a terrifying and even more ambitious thriller that delves into the shocking truth of what drives human beings to violence, genocide, and war.