In the strongest scenes of ''The Notebook,'' the screen adaptation of Nicholas Sparks's treacly best seller, Ryan Gosling and Rachel McAdams break through the barrier to evoke high-strung, slightly crazed teenagers plunging headlong into first love. It is passion that begins in playfulness. Their performances are so spontaneous and combustible that you quickly identify with the reckless sweethearts, who embody an innocence that has all but vanished from American teenage life. And against your better judgment, you root for the pair to beat the odds against them.
The romantic drama, directed by Nick Cassavetes from a screenplay by Jeremy Leven and adapted by Jan Sardi from the novel, opens today nationwide. It is told in flashback as Duke (James Garner), a garrulous, ailing old codger in a comfortable nursing home, reads aloud excerpts of a love story to Allie Calhoun (Gena Rowlands), a patient suffering from Alzheimer's. She is so smitten with the 1940's tale of Noah (Mr. Gosling), a poor Southern boy who works in a lumberyard, and his wealthy girlfriend, also named Allie (Ms. McAdams), that for brief intervals his readings jog her blurred memory into focus.
As the movie seesaws between Seabrook, N.C., in the summer of 1940, when Noah and Allie meet at a fairground, and the present, it is deliberately (and annoyingly) coy as to who these oldsters might be. Gosh, could they be the same young lovers six decades later?
Mr. Garner and Ms. Rowlands are wonderful actors, but Mr. Garner, in particular, plays ''old'' with a hammy avuncularity that sugarcoats his character with a glaze of nostalgia. His performance reinforces the impression that in Hollywood, old age is even more difficult to depict with real honesty than young love. Ms. Rowlands's Allie is quieter and sadder, but she looks too well-preserved for a woman in her condition, and as the story leaps back and forth, the movie veers between unbleached sugar and artificial sweetener.
When Noah meets Allie, he is so desperate to impress her that he hangs on the rungs of a Ferris wheel and threatens to jump if she won't go out with him. Even at the beginning, Mr. Gosling's performance emphasizes Noah's slightly creepy streak of fanaticism. After the lovers have separated, he withdraws into himself, grows a beard, and with a small inheritance from his poetry-loving father (Sam Shepard), a Walt Whitman fan, he converts the rotting old mansion he once dreamed of sharing with Allie into the showplace he promised to build for her. He also serves in World War II, where he sees his best friend die in the Battle of the Bulge.
Ms. McAdams, who played the alpha queen in ''Mean Girls,'' matches Mr. Gosling's Noah in idiosyncratic verve. Impulsive, giggly and combative, she exudes the air of a careless rich girl bursting out of a bubble, until the moment her stern, watchful mother, Anne (Joan Allen), puts her foot down and ends the relationship.
The scenes between the young lovers confronting adult authority have the same seething tension and lurking hysteria that the young Warren Beatty and Natalie Wood brought more than 40 years ago to their roles in ''Splendor in the Grass.'' The power of Ms. Allen's performance comes out of understatement. Impeccably coiffed and outfitted, barely moving her tight lips, she projects the full emotional depth of composure under siege.
Like most movies that span many decades, chapters of ''The Notebook'' seem scrunched together. The war, in particular, passes in a flash. It is as a nurse's aide that Allie meets Lon (James Marsden), a dashing, seriously injured soldier from a wealthy Southern family. Once recovered, he courts Allie aggressively and, just when the beautiful couple are on the verge of marrying and becoming the toast of Charleston society, she reads a newspaper article about Noah's architectural restoration and promptly faints. A reunion is in order.
For a movie that might have plunged full-scale into bathos, ''The Notebook'' tries to remain restrained. The camera caresses the lush Southern landscape of blood-red sunsets and flocks of ducks, and Aaron Zigman's romantic score drizzles only a light coating of syrup over the ice cream.''The Notebook'' is a high-toned cinematic greeting card. It insists on true, mystical, eternal love, till death do us part, and won't have it any other way.