Cornwall, 1940. For decades, Penhallow Hall has stood frozen in time, protecting the secrets of its isolated inhabitants. But the far corners of England are no shelter from the war, and Penhallow must finally open its doors to strangers. Three newcomers arrive, each looking to escape their past. They adjust easily to the routine - nightly blackouts, the threat of invasion - but tensions mount and secrets are forced into the open. For one of them is not there by choice. And then, in the hushed hours of deepest night, a young woman is taken by the sea.