On a beautiful Saturday in downtown Saint Paul, Minnesota, investigator Kirk Stevens and his occasional colleague FBI special agent Carla Windermere witness the assassination of one of the state's wealthiest men. The shooter is a young man, utterly unremarkable - except in his eyes. There is something very wrong in his eyes. And it's only the beginning. The events will soon lead them across the country, down countless blind alleys, and finally to a very flourishing 21st-century enterprise: a high-tech murder-for-hire social media website.