The woman who discovers the letter is Theresa Osborne, a journalist living in Chicago who has recently gone through a painful divorce. She is drawn to the letter's heartfelt prose and sets out to find its author. With some sleuthing, she discovers that the letter was written by a man named Garret Blake, who lives in a small coastal town in North Carolina.
Theresa travels to the town and meets Garret, a ruggedly handsome man with a troubled past. Garret is a skilled shipbuilder who has been struggling to come to terms with the death of his wife Catherine, who drowned in a sailing accident several years earlier. He writes letters to her and puts them in bottles, which he sends out to sea in the hopes that they will reach her.
As Theresa and Garret spend time together, they develop a deep connection, but Garret is hesitant to fully open up to her about his past and the pain he still carries. Meanwhile, Theresa's ex-husband shows up and tries to win her back, causing her to question her feelings for Garret.
Eventually, Garret's secret is revealed when Theresa finds one of his letters to Catherine. She confronts him about his reluctance to let go of his grief and encourages him to find a way to move forward. Garret realizes that he has been holding on to his pain for too long and finally lets go.
In the end, Garret and Theresa confess their love for each other and start a new life together. They continue to write letters to Catherine, but now they are filled with gratitude for the time they had with her and the love that they have found in each other.