In 1936 Britain is facing a political and constitutional crisis. The fascist British Union are edging towards power, the king’s American mistress threatens to destabilise the monarchy, and secretive forces are manipulating events for their own ends. Hugh Clifton is trapped in his role as an MI5 informer within the fascist headquarters, taking over Room Z and recruiting his lover Sissy as one of his agents. Investigating a simple burglary, they uncover murder and a rapidly spiraling web of intrigue. The Agents of Room Z race to unravel competing conspiracies that entangle the government, the church, and the king in a deadly struggle for the very future of the country.