As the sun sets on St Agnes on bonfire night, a man's charred body is found on Burnt Island, surrounded by threats in the old Cornish language.Deputy Chief of Police Ben Kitto has no choice but to ban all travel between the islands, forcing the community of just eighty islanders to remain within reach, while he hunts for the killer. Ben quickly suspects the motive is to rid the island of newcomers who threaten tradition, and when a second fire results in the disappearance of another islander, he only has forty-eight hours before another life is lost.