Against the backdrop of Newfoundland's craggy rocks and turbulent seas, marine biologist Finleigh Farraway finds the buried journal of World War II veteran Liam Crowley. The journal's shocking content turns Finleigh's world upside down and launches her on a quest that changes everything.

The journal begins in 1941 with the Battle of the Atlantic raging and St. John's a vital port. Liam finds himself on leave and travelling to a remote beach where he stumbles upon a peculiar woman wearing only a nightdress. As their relationship develops, her unusual behaviour captivates him. Unfortunately, she harbours a devastating secret, one that threatens to tear them apart.

With the newfound journal on her mind, Finleigh's marine research takes her to the wild, western coast of Ireland. While there, she searches for answers to the decades old mystery that lies within Liam's story. Her unexpected discoveries leave Finleigh reeling and, ultimately, questioning everything she's ever known to be true about what lies beneath the ocean's surface.