In 2005, novelist Peter May found himself in quite the conundrum – how does one write the next bestseller? When his sixth book made mediocre waves in the industry, he was dropped by his publishers. When his next two books, The Blackhouse and Extraordinary People failed to find a home, he needed a plot that would sell. What story could do just that? Perhaps a pandemic thriller?

He envisioned a plot where bird flu (which scientists had predicted to be the next pandemic) had shut down a major city. May mulled over capitals in his mind. He first flirted with the idea of Beijing and then Paris but, of course, what better setting than London, for chaos to unravel.