Eighteen years ago, writer-director Richard Linklater (2012's "Bernie") released what was, and arguably still is, his most formidable achievement as a filmmaker, the sweepingly romantic "Before Sunrise." Set over a single day and night in Vienna, the picture told of 23-year-old strangers, the American Jesse (Ethan Hawke) and French Celine (Julie Delpy), meeting on a train and deciding to spend the last hours of their travels together before parting ways. In that time, a spark was lit and actual love blossomed, but, in this particular time and place in their lives, it was unrealistic for them to be together when they weren't even living in the same country. In 2004's lovely "Before Sunset," Jesse and Celine met again nine years later, now in their thirties and with a great deal more baggage to overcome. That same magic was still there, however, and the film ended somewhat ambiguously, suggesting without confirming that the now-married Jesse's stint in Paris—he was on a book tour for his debut novel, based on the day he and Celine met—would be lasting a bit longer than originally expected. As we grow older, the passage of time seems to accelerate and we are faced with our own mortality—a notion at the wise and poignant heart of "Before Midnight," the third installment in this unexpectedly potent series. Though another nine years have passed and these now-beloved characters are in their early forties, the same soaring, unforced chemistry is still very much there between Jesse and Celine (and Hawke and Delpy, for that matter).

With their six-week vacation to the southern Peloponnese of Greece coming to an end and Jesse having just bid farewell to his 13-year-old son Hank (Seamus Davey-Fitzpatrick), who lives in Chicago with his mother, he and Celine are begrudgingly facing a return to the real world. Together since we last saw them and with twin daughters Nina (Charlotte Prior) and Ella (Jennifer Prior), Jesse and Celine have never married but are very much a couple. Though there is still that same spark between them, that back and forth give-and-take that brought them together in the first place, things are not perfect for them—a truth that is only exacerbated as long-harboring resentments rise to the forefront during a would-be romantic night together.

"Before Midnight" feels very much as it should: an organic extension of the lives of two people first introduced eighteen years ago in "Before Sunrise." In that time, Jesse and Celine have altered their outlooks, become more practical and less wide-eyed, and grown just a little more cynical with age. Chalk it up to their natural evolution as they rack up experiences and approach middle-age, the knowledge that their lives are half over forcing them to consider all the things they have yet to do that they want to. Jesse is still a novelist, though one who hasn't had the same success as he did with his first two books, while do-gooder Celine is prepared to take a government job that will earn her far more money than she's been making. The two of them discuss Celine's planned career change on their way back to their villa from the airport, then share a nice dinner and conversation with their elderly host (Walter Lassally) and fellow vacationers. From there, it is off for a picturesque walk into town and to the hotel room that's been prepared for them.

The bulk of "Before Midnight" is airy yet provocative, thoroughly involving and deliciously written by Richard Linklater, Ethan Hawke and Julie Delpy, the give-and-take between Jesse and Celine as richly observed and lived-in as one might expect from a couple who have been together for nearly a decade. While dramatic tension in "Before Sunrise" and "Before Sunset" was limited mostly to what they would do once their time together was over, "Before Midnight" ups the ante in a centerpiece third act set in their hotel room where an evening of fun and intimacy gives way to accusations about their faithfulness, grudges they claim the other has been holding, and responsibilities that have kept them from fulfilling their professional goals. Things get very heated—too heated, actually, with Celine especially written to be one-sided, accusatory and irrational—leading to, well, each individual viewer will have to see for themselves. The final minutes are tough and bittersweet, but also, thankfully, reassuring.

Ethan Hawke (2012's "Sinister") and Julie Delpy (2005's "Broken Flowers") are emotionally available in every moment of "Before Midnight," and for fans who have been following Jesse and Celine for nearly two whole decades the experience is like eavesdropping on old friends the audience has come to have an invested interest in. Where director Richard Linklater temporarily runs into a spot of trouble is the insinuation that they are no longer soul mates, but romantic partners with the threat of splitting up constantly dangling overhead. This is never—or shouldn't be—a question for true loves meant to be together, and so it comes as a bitter disappointment to know that maybe Jesse and Celine aren't the "perfect" fit after all. Fortunately, the film's less idyllic view of love leads to a certain redemption—one that does bring hope to two people with a lot of problems, but also a bond that hopefully will aid in weathering the storm. This, too, hopefully, shall pass. "Before Midnight" lacks the sweeping romanticism of "Before Sunrise," replaced by the realities of one's day-to-day existence in a world where things don't always turn out the way one imagines, or hopes. Such is life.