When sisters Celine and Pip get a call telling them their reclusive mother has died, the women are reunited at her riverside home in Arundel to pick up the pieces. But someone is missing—their middle sister, Vanessa, brutally murdered years ago and the victim of an unsolved case. As the sisters confront ghosts from the past, the discovery of another body in similar circumstances throws new light on Vanessa's death. Could there be more to her case than the police first thought? And what do the mysterious residents of Two Cross Farm, the neighboring women's commune, have to do with it? What secrets are lurking behind their locked gates? And what is the significance of the number 33?