Welcome to Eris: an island with only one house, one inhabitant, one way out. Unreachable from the Scottish mainland for 12 hours each day. Once home to Vanessa, a famous artist whose notoriously unfaithful husband disappeared 20 years ago. 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.

When a young man is found gruesomely murdered in a London houseboat, it triggers questions about three women who knew him. Laura is the troubled one-night-stand last seen in the victim’s home. Carla is his grief-stricken aunt, already mourning the recent death of yet another family member. And Miriam is the nosy neighbor clearly keeping secrets from the police. Three women with separate connections to the victim. Three women who are --- for different reasons --- simmering with resentment. When it comes to revenge, even good people might be capable of terrible deeds. How far might any one of them go to find peace? How long can secrets smolder before they explode into flame?

A single mother turns up dead at the bottom of the river that runs through town. Earlier in the summer, a vulnerable teenage girl met the same fate. They are not the first women lost to these dark waters, but their deaths disturb the river and its history, dredging up secrets long submerged. Left behind is a lonely 15-year-old girl. Parentless and friendless, she now finds herself in the care of her mother's sister, a fearful stranger who has been dragged back to the place she deliberately ran from --- a place to which she vowed she'd never return.

Rachel takes the same commuter train every morning. Every day she rattles down the track, flashes past a stretch of cozy suburban homes, and stops at the signal that allows her to daily watch the same couple breakfasting on their deck. She’s even started to feel like she knows them. Their life --- as she sees it --- is perfect. Not unlike the life she recently lost. And then she sees something shocking. It’s only a minute until the train moves on, but it’s enough. Now everything has changed.