Online payment service Wirecard was once Germany's biggest tech darling and the country's answer to Silicon Valley, at its peak valued at more than 24 billion euros; until 2020, when it was exposed as one of the most audacious corporate frauds of the modern era. A tip-off in 2014 started Financial Times journalist Dan McCrum on a seven year investigation, uncovering corrupt business practices and fraudulent financial reporting. But as he pursued the story, Wirecard fought back viciously; with online abuse, hacking, electronic eavesdropping, physical surveillance and intimidation. But t...