 The events of "Camber the Heretic" span roughly one year, from January 917 to early January 918.The novel begins as the Deryni Healer Rhys Thuryn and his wife, Evaine MacRorie Thuryn, attempt to treat an injured colleague, Earl Gregory of Ebor.While tending to Gregory's wounds, Rhys accidentally discovers an innate ability to block Gregory's Deryni powers.