Rose Castle has begun a therapy journal to cope with the difficulties in her marriage. In her first journal entry, Rose writes that her husband Owen left ostensibly because of a job opportunity in London. The real reason could be Rose’s desire to have a child and her trouble getting pregnant. Rose can’t join Owen anyway, as she has to take care of her twin sister Fern, who is her responsibility. Rose recalls her traumatic past. One incident in particular stands out: When she and Fern were 12, their mother Nina’s boyfriend Daniel joined them for a camping vacation. Daniel brought along his son Billy, and the girls loved having a brother-figure around. On the last night of the trip, the children went for a swim in a river near the campsite. Fern was in a peculiar mood that night. Rose remembers Billy was swimming when she had to go to the woods to answer “nature’s call” (1). When Rose returned five minutes later, Billy was nowhere to be seen. She spotted Fern, standing “eerily still” (2) in the shallows. Billy’s pale body rose to the surface of the water next to her.