The story is set in the Orcades, the remote Scottish Orkney Islands in the North Atlantic. More than fifty individual bells hang on steel hoops over the graves of the Fergus family burials on Grave Hill. Each of these is tied to a cord, which passes down through the earth to a hand of the corpse below to summon help should a Fergus be buried alive. Could their death-like seizures be related to the yearly change of Finfolk from sea creatures to humans in the spring and back again in the fall? Is the family cursed by their supposed Finfolk ancestry or is the story simply folklore? The answer is to be found on the enchanted North Sea island of Eynhallow, the reputed home of the slimy Finfolk sea creatures. There, a witch, a priest and the Fergus family members are drawn into a battle against murderous sea beings that come in the fog, a battle that began in a time long before recorded history.