Welcome to Eris: a remote Scottish island with only one house, one inhabitant, one way out. Unreachable from the Scottish mainland for twelve hours each day. Once home to Vanessa: A famous artist whose notoriously unfaithful husband disappeared twenty years ago in a baffling cold case. Now home to Grace: A solitary creature of the tides, content in her own isolation. But when a shocking discovery is made in an art gallery far away in London, a visitor comes calling. And the secrets of Eris threaten to emerge....