Josephine Haven is about to find out exactly where she fits into the march of Progress. Her outbursts are infamous at the House of Industry, the school for children who can wield radiance, an electricity-like magic. She's tried to follow the rules, but her fiery nature is at odds with the core tenet of the House: Never form attachments. If she is meant to feel nothing, why are her emotions so volatile? No one is surprised when, upon graduation, Josephine is banished from the city to a remote Mission. In Frostbrook, she must work under standoffish Julian, the former golden boy of the House of Industry who seems determined to watch her fail. And then there's Ezra, the flirtatious stranger who's a little too curious about how the Mission operates. But there are bigger problems than Julian and Ezra's secrets. A deadly disease is spreading across the countryside, and in Frostbrook, not everyone is eager to embrace Progress. As Josephine questions the system that raised her--and gives in to desire she's been taught to suppress--she must decide what she's willing to sacrifice to expose not just corruption within the House but the devastating truth about the radiance in her core.