One evening, ten-year-old Louisa and her father, Serk, take a walk out on the breakwater. They are spending the summer in a coastal Japanese town. Hours later, Louisa wakes on the beach, soaked to the skin.

Her father is missing: presumably drowned. This sudden event shatters their small family. As Louisa and her American mother return to the US, Serk's disappearance reverberates across time and space, and the mystery of what really happened that night slowly unravels.