Everyone thinks Arthur is a nobody — a minimum-wage night guard at the Tower of London, dumped by his arrogant fiancée Emma and humiliated by the mayor's son Marcus, who throws cash in his face and tells him to fetch coffee. None of them know that the "worthless loser" they mock is an immortal knight who has secretly guarded this city for a thousand years.
When Arthur glimpses an ancient cult mark beneath Marcus's collar, a millennium of memory comes roaring back: Marcus is the high priest of a doomsday sect, and tonight he intends to sacrifice all of London to resurrect the dark god Sargoth. As blood-red storms swallow the sky and ghost armies claw out of the earth, Arthur must reclaim the holy sword he sealed away centuries ago — and become the warrior the world forgot.
To save millions, he'll burn sixty years of his immortal life to awaken the Thunder War God within. And when the city is saved, the woman who threw him away comes crawling back, penniless and begging — only to watch the god of war walk silently past her, back to his lonely post.
