Former UN investigator Gerry Lane is thrust into a chaotic world turned upside down by a sudden and mysterious outbreak that transforms the infected into aggressive and unthinking predators. Amidst the panic and turmoil of mass evacuations, Lane, along with his wife Karin and their two daughters, narrowly escapes the rapid onslaught consuming the city of Philadelphia. After a harrowing journey, they are airlifted to safety on a U.S. Navy vessel out at sea, where Lane learns that the epidemic has spread worldwide. Countries and cities are falling into chaos as governments struggle to contain the rampant spread of the disease.

Urged by his former UN colleague, Thierry, and owing to his expertise in dangerous global affairs, Lane is coerced into returning to the field to help investigate the source of the outbreak. He sets out on a perilous mission that takes him around the globe in search of answers that could potentially stop the terrifying pandemic. From the besieged streets of Jerusalem to the remnants of a WHO research facility, Lane must unravel the mystery of the virus's origins and its weaknesses while navigating through the untold dangers of a world overrun by the infected—a world teetering on the brink of collapse.