Detailing the unlikely romance between Theresa Osborne and Garrett Blake. The narrative begins by tracing the voyage of a message in a bottle—written by Garrett to his deceased wife, Catherine—until it washes ashore and is discovered by Theresa, a columnist recently divorced and struggling with loneliness in Boston. Driven by curiosity and encouraged by her friend Deanna, Theresa investigates the letter's author, leading her to Wilmington, North Carolina, and to Garrett, a dive shop owner and sailor who is still profoundly mourning Catherine. Their subsequent relationship blossoms through sailing and shared time, facing the challenge of long distance and Garrett's inability to fully move past his late wife, a struggle dramatically resolved only by his tragic death at sea, which is revealed to Theresa by his father along with Garrett's final letter professing his love.