The Notebook starts in an nursing home where the main character and narrator, Noah Calhoun, is reading a story from a notebook at the bedside of an old woman and Alzheimer's sufferer.

He tells her of the story of the 31 year old Noah returning to his home town in North Carolina from the Second World War. At this point he has very little in his life. He has lost his best friend and has no wife or girlfriend. The girlfriend he had before he left, Allie Nelson, never returned his letters. He is therefore surprised when she arrives unannounced at his door.

She tells him that she never received his letters and guesses that her mother, who never liked Noah because of his lower social standing, hid them. Now, she says, she is engaged to a lawyer called Lon.

The two of them agree to have dinner for old times sake, but it soon becomes apparent that they still have feelings for each other. At first, Allie rebuffs Noah's advances, reminding him that she is about to get get married. However, she can't hold out for long. After a day out on the lake reminds her of her happy past and ambitions to become a painter, the two make love at Noah's home.

In the morning, Allie's mother arrives to give Allie Noah's letters and to tell her to follow her heart. Noah's story finishes with Allie talking to her fiance Lon in a parking lot. The narrator does not reveal what they say.

Back at the nursing home it is revealed that the old woman Noah is reading to is his wife Allie. The novel ends with Allie finally remembering who Noah is and telling him that she loves him.

This is a love story taking place in the past and the present.

Although the narrator is in the present, most of the action of the story takes place in 1946 as a flashback.  An old man named Noah is reading to an old woman.  Noah is poor, and Allie is rich.  Noah is in love with Allie, but they are separated and he sends her one letter a month but she does not respond.  Noah inherits a fortune, but regrets that Allie has not returned any of his letters.  She has not received any.  Noah has returned to his hometown, and bought an old plantation to restore.

He was thirty-one now, not too old, but old enough to be lonely.  He hadn’t dated since he’d been back here, hadn’t met anyone who remotely interested him. (ch 2)

Noah runs into Allie, and she seems to still love him.  Back in the present, Allie has Alzheimer’s and no longer remembers who he is, even as he reads her their story.