In 14th Century Languedoc, after a century of persecution drove the Believers underground, a revival of the Cathar heresy gains a foothold in the mountain villages of the County of Foix. As it sweeps around the region, two men leave their homes and families and become embroiled in the forbidden faith.

Based on Inquisition records archived for nearly 700 years in the Vatican, this is a fictionalised account of the epic, true story of these two men, Pierre Maury (Pedro, the shepherd) and Guillaume Belibaste (Guy), who was fated to become the last of the Cathar Holy Men (Perfects).

As the Inquisition launch a brutal campaign against them, the men must again leave their loved ones and seek safety across the border in Aragon. As many Perfects are burned alive and friends and family are arrested, can Guy and Pedro stay safe? And can their faith and their friendship survive as the Inquisition become closer and ever more brutal?