One winter's afternoon, Sonia opens the door of her beautiful riverside home to fifteen-year-old Jez, the nephew of a family friend. He's come to borrow some music. Sonia invites him in and soon decides that she isn't going to let him leave.

As Sonia's desire to keep Jez hidden and protected from the outside world becomes all the more overpowering, she is haunted by memories of an intense teenage relationship, which gradually reveal a terrifying truth. The River House, Sonia's home since childhood, holds secrets within its walls. And outside, on the shores of the Thames, new ones are coming in on the tide...