Appalachia, 1850. A generation ago a group of Welshmen came across the ocean to build a new existence and with them they brought their own traditions and rituals. One of them is the sin eater, a mysterious person, forced to live in the woods and mountains, only to come out when somebody dies. He then pawns his own soul to take away the sins of the deceased. 10 year old Cadi Forbes meets the sin eater for the first time at the funeral of her grandmother and is immediately intrigued. Cadi is torn by guilt over the death of her little sister Elen and wants the sin eater to redeem her. With the help of Fagen, son of the ruthless village leader Brogen, and the imaginary Lilybet, she starts a search to find him, but by doing so Cadi slowly, but surely unravels dark and terrible secrets.