Dr Megan Banesto has returned to her childhood home in Llancloudy in the Welsh valleys. As the local GP, she feels she knows her patients well. So when the body of paranoid schizophrenic Bianca Rhys is dragged from a murky pool, Megan becomes suspicious. The official verdict is suicide but whey would someone afraid of water go near the pool?

Investigating officer PC Alun Williams happens to be Megan's old flame and, rather than take the young GP seriously, he sees Megans' interest in the case as simply a ruse to keep in contact with him. But as Megan discovers more about Bianca she becomes intrigued by the outlandish claims she used to make. What if Bianca was the only one who knew what was really going on in Llancloudy?