Journalist Zoe Beck has taken a break from hard-hitting investigative reporting to spend more time with her family, which is how she finds herself doing celebrity Q&As at an outdoor music festival near the Scottish border. She and her friends, who run a food truck, head north, along with 150,000 festival-goers for a weekend of music and camping.

Then, some of the food truck’s customers begin to fall ill, and many point to food poisoning. But when the festival ends and the attendees scatter across England, more people begin to get sick and die. What’s worse, it is spreading fast and baffles doctors, resisting all efforts to contain or cure it. With time running out, Zoe is compelled to fight for the truth, even as she loses that which she holds most dear.