Keystone goes to battle with their most fearsome foe yet in this USA Today Bestselling series by Dannika Dark. In the world of crime fighting, Raven has learned that formal affairs are a necessary evil. So when Keystone receives an invitation to a winter ball, she tries to make the best of it. The most powerful elites in Cognito are attending—a perfect opportunity to network and have a few drinks. But when a guest hijacks the party in a violent display of dark power, chaos ensues. It’s a race against time as Raven searches for a way to thwart his diabolical plan. Will Keystone find the fortitude to prevent the downfall of civilization? Or will they bow to a new king to save their souls? “And a terrible curse befell the winter ball.”