An ordinary man lives an ordinary life, until one day she walks into the bar and everything changes. It could be Rick and Elsa in Casablanca, but in Haruki Murakami's brief yet absorbing new novel, South of the Border, West of the Sun, it's Hajime and Shimamoto in Tokyo.

Hajime was a shy, suburban only child, convinced that "everyone in the whole world lived in a single-family home with a garden and a pet, and commuted to work decked out in a suit." Twelve-year-old Hajime is torn from his solitude at school when he is asked to help out a new student, Shimamoto. Her left leg stunted by polio, Shimamoto was equally quiet, but unlike Hajime, she faced the world with tough self-possession. Listening to records at Shimamoto's house, the two begin a bashful courtship that awakens in Hajime the wonderful possibilities of shared emotion.

"We were, the two of us, still fragmentary beings, just beginning to sense the presence of an unexpected, to-be-acquired reality that would fill us and make us whole. We stood before a door we'd never seen before."

Their growing unity comes to an end when Hajime moves to another town and enters another school. Although always in his memory, Shimamoto's emotional presence fades as Hajime moves on to high school, where he acquires a girlfriend, Izumi. Soon he allows his adolescent lust to betray her. Unbeknownst to him at the time, his burgeoning, selfish sexuality will destroy not only their relationship, but Izumi herself.

Time passes. Hajime graduates from college, acquires a job and a wife, and before he knows it, finds himself the father of two children and owner of two jazz clubs. Happily married, financially secure, and absorbed in his job, thirty-seven-year-old Hajime is coasting into quiet, comfortable affluence until, one night, looking up from his book, he sees a strange and beautiful woman seating herself at his bar. His life is about to change, for the expensively dressed, gorgeous woman lighting a cigarette and ordering a drink is Shimamoto, whom he has not seen for twenty-five years.

Thunderstruck, he tells Shimamoto, "Everything disappears someday. Like this bar-it won't go on forever. People's tastes change, and a minor fluctuation in the economy is all it'd take for it to go under. I've seen it happen; it doesn't take much. Things that have form will disappear. But certain feelings stay with us forever."

And Hajime's feeling is, of course, love. "Her eyes were like a deep spring in the shade of cliffs, which no breeze could ever reach. Nothing moved there, everything was still. Look closely, and you could just begin to make out the scene reflected in the water's surface."

If this sounds like the plot of a forties movie, you're not far wrong. And that's part of the pleasure of Murakami's sensibility: as a master of pop culture, he knows how to ease the reader into a warm tub of familiar nostalgia, but his mastery of limpid plotting keeps the reader engaged. You've heard this story of emotional entropy before, but it's still terribly engaging.

As Shimamoto observes, "the sad truth is that certain types of things can't go backward. Once they start going forward, no matter what you do, they can't go back the way they were. If even one little thing goes awry, then that's how it will stay forever."

First introduced to American readers with 1989's A Wild Sheep Chase, Murakami has been best known for his wild inventiveness, mining American pop culture for material like Dennis Miller on a speed-rant, crossing science fiction and crime stories as well as the master himself, William Gibson. Critics have found in Murakami's writing traces of Abe, Mishima and Kawabata, as well as a host of American cousins.

However, South of the Border, West of the Sun is an enormously subdued performance. It's no criticism of his previous writing to say that this is a mature work, one that eschews the referential fireworks for the longer lasting coals of emotional observation. What could have been simply a diverting tale of amour fou is instead, in Murakami's hands, a story about the staying power of emotional ties, and how that if love and happiness intersect, it's a mere coincidence.