"MI5 agent Sam Tilson stumbles upon a forgotten World War II operation while combing through declassified files at The National Archives. What begins as a routine task unearths a dangerous mystery—a Nazi experiment involving a weapon codenamed Blitzspeer – Lightning Spear, hidden deep in the Bavarian Alps. Partnered with historian and intelligence asset Dr Ingrid Lang, who carries secrets of her own, Tilson is thrust into a deadly web of rogue intelligence agents, drug dealing, and a neo-Nazi conspiracy."