Escaping from a disastrous relationship, Kathleen Devine flees to an isolated lighthouse off the Victorian coastline. Taking up the position of Head Teacher to the lighthouse keepers' children, she is ensnared in the lives of those marooned on the lonely outpost and soon realises no-one can escape their past. When the fearsome Head Lightkeeper, Mr Johannsson forms an unlikely friendship with the daughter of one of the keepers, it threatens to destroy their fragile peace. Can Kathleen find the strength to survive and answer the question that haunts them all: what happened to Isabella and why?