Twelve-year-old Lark Heron-Finch returns to Swallowtail Island for the first time since her mother's tragic death. While trying to reconnect with her family's past, she stumbles upon a decades-old mystery surrounding a shipwreck. With the help of new friends, Lark uses her sharp mind and love of sailing to uncover long-buried secrets that powerful people want to keep hidden. This thrilling summer adventure shows that courage and truth can heal old wounds.