"The Notebook" tells the story of how Noah Calhoun and Allie Hamilton meet and fall in love in 1940s South Carolina, on Seabrook Island. Noah narrates the story in flashbacks to Allie.
The movie opens on a scene in a contemporary nursing home. Nick and Allie are both old and have children and grandchildren. Allie has dementia and cannot remember most of her past. Each morning, Noah reads their love story to her from an old notebook.
Noah and Allie first meet at a carnival and enjoy an intense summer love affair. Allie's parents, who intend for her to marry into wealth, bar her from seeing Noah again, denouncing him as trash. Noah and Allie drift apart. Noah writes Allie, but she never writes back. Noah enlists in the Army.
Allie subsequently marries Lon Hammond Jr., a young, rich, handsome lawyer who comes from old southern money. Meanwhile, Noah returns to South Carolina and restores an old country house according to specifications Allie shared with him during their affair years prior.
Allie reads about Noah's activities in a local paper and visits him in his restored house on Seabrook Island. The lovers rekindle their romance. Allie's mother, Ann, comes to Noah's house and warns Allie that Lon followed her. Ann produces Noah's old letters, which she prevented Allie from seeing years ago. Allie abandons Lon at a nearby hotel.
In the present, Allie has a moment of remembrance, and she recalls how she and Noah fell in love. Noah recovers from a light heart attack and returns to Allie at the nursing home. He climbs into bed with her, and the lovers die in an embrace.