Born Eunice Waymon in North Carolina, she lived her last, crusty years and died in France. But no matter what country its setting, any film astute enough to close with, and extend into end-credits, the voice of Nina Simone, is a winner to me. That Before Sunset features beguiling performances, a heart that most anyone can relate to, and a final context-pregnant two-liner, is icing on the cake.

Standing on its own, not a mere easy sequel to his 1995 deeper than just first love Before Sunrise, Richard Linklater’s latest reunites stars Ethan Hawke (in his fifth film for the director) and Julie Delpy, nine years later. Not about the concept of changing the past, the story inserts brief new bits of the first film’s fourteen hours in Vienna but is largely concerned with uncovering personality below protective social surfaces and with changing the present moment and thus, though left openly ambiguous, the future.

“Just in Time” is the song referred to above, and one may think, too, of Dooley Wilson’s rasped “As Time Goes By.” Scott Fitzgerald elsewhere doubted the possibility of second acts in American lives but his fatally innocent Gatsby fails because Daisy Fay was neither in past nor present -- “in the meantime,/In between time” -- the woman he dreamed. In contrast, Rick Blaine and Ilsa Lund are forever together in that they do part for a higher cause than love’s hill of beans, but that was a different time.

Here it is 2003, nine years have passed since Gen-Xers Jesse Wallace and Céline nearly committed themselves during the last half-day of his Eurail pass. Pledging to meet again on December 16, and so confidently not exchanging contact numbers, they have gone separate ways, new lives, since her beloved grandmother’s funeral preempted her appearing. Not entirely, however: she from Paris to New York for a Master’s Degree, he from Texas to New York, they had been oh so close, perhaps even crossed, he sighs, on Broadway and Thirteenth.

They are now in their early thirties, she working for environmental Green Cross and, with a pile of dead-end relationships and a current absent photojournalist beau, despairing of fulfillment in love; he with an adored four-year-old son, an attractive efficient wife but already stale marriage, and acclaim for a first, “autobiographical” novel about a young couple who share in Vienna the last fourteen hours of a train pass.

On the last leg of a tiring ten-city, twelve-day book promotion tour, he sleeps in the loft above Sylvia Beach’s Shakespeare & Company. Not really because this is her favorite bookstore, Céline nervously hovers at his press Q&A, after which the two set off into the City of Light afternoon to rediscover one another before his flight. Unusually shot in the “real time” of Aristotelian unity -- which restricted filming to certain few hours during the three-week shoot -- the film will give them eighty minutes, no more.

Rigorously, there are only these two characters, against unfocused backgrounds, and their dilemma will come to revolve about joyous laughter in life or the lack of it, the risky promptings of the emotions vs. social pretense.

The two stars and director share screenplay credits, as apparently great chunks of the dialogue were worked out by e-mail. Talky, minimal in character and outward action, the situation places a tremendous burden on the actors and their lines, and, at first, all seems artificial and awkwardly delivered. Perhaps this is intentionally done, to show a guardedness only natural in the circumstances; shortly, however, Hawkes and Delpy loosen up or Jesse and Céline do -- and, despite a couple of jarring four-letter words and lame anti-gun spiel, talk about the things that anyone would. So much so that, as they win the audience and make it forget all the outside world except the two of them, it seems effortlessly extemporaneous and not, as claimed, entirely scripted.

Their real- and screen-time’s chariot hurrying near, the hero and heroine dally until the final minutes to strip off onionskin layers of pretense to reveal the insecure yet hoping heart beneath. Obvious, yes, but so nicely done that one does not object and is even pleased that, though it may reek of “sequel,” an open ending leaves room to imagine. James M. Barrie once posited a sagging, ill-matched, years-down-the-road Cinderella and her Prince, just as Jesse fears being fifty-two and trapped; whatever he and she decide, whether they “stay together or dissolve into molecules,” theirs is the present moment. As the song says, “I’ve found my way, so let’s live today.”

(Released by Warner Independent Pictures and rated “R” for  language and sexual references.)