LOS ANGELES - Movie romances typically focus on how two people connect rather than what makes them stay together - on the excitement of the chase, or of a love thwarted and then triumphant, rather than the day-to-day negotiations of a long-term relationship.
Before Midnight, which follows the same couple who first met in the film Before Sunrise (1995) and then reconnected nine years later in Before Sunset (2004), focuses on this second, less glamorous part, with all its joys, frustrations and arguments big and small.
It reunites director Richard Linklater with actors Ethan Hawke and Julie Delpy, who reprise their roles as Jesse and Celine - a couple who first met on a train to Vienna two decades ago, when she was a university student in France and he, a young American backpacking through Europe.
They found each other again in the second film, when Jesse goes to Paris to promote a book he wrote that was inspired by their initial meeting. The two movies have become cult hits.
The third movie, which opens in Singapore tomorrow, leaps forward another nine years: They are now a couple and seemingly settled into their life together, but while on holiday in Greece with their twin girls and Jesse's son from a previous marriage, they find themselves re-examining their relationship.
During a press conference for the film in Beverly Hills this year, the director and his two stars, who co-wrote the screenplay with him, said they set out to make a truthful love story, warts and all.
In doing so, they drew on their own experiences.
Hawke, 42, has a chequered romantic history not dissimilar to his character's, with his relationship with wife Ryan Shawhughes allegedly responsible for the break-up of his previous marriage to actress Uma Thurman, and two children from each union.
He says: "It's very easy to look at a romantic relationship when there's an obvious bad guy - you know, when one person is an alcoholic or abusive.
"But what if you were to take two well-meaning people who actually love each other and want the best for each other? It's still hard. Could we paint that portrait?"
The dilemmas faced by Celine and Jesse will be familiar to anyone who has been in a long relationship, says the American actor, who has appeared in films such as Reality Bites (1994), Gattaca (1997) and Training Day (2001).
The question is often "whether or not your lives are still growing on the same road, or does one need to change the road to keep growing".
For Delpy, a 43-year-old French-American actress who has a four-year-old son with former boyfriend Marc Streitenfeld, a film-score composer, the trilogy charts the evolution and "life of a relationship" - one that has progressed to a point where it is all about tough choices and compromises, and there is only so much room "for it to not fall apart".
Linklater, who has had his characters age in real time over the 18-year span of these films, wants the third to explore some aspects of what happens as couples get older.
"In the first movie, they're unattached and you see how easily they can get off a train or go home a day later - you had that looseness," says the 52-year-old, who was one of the leading lights of American indie cinema in the 1990s, when he made the 1993 coming- of-age classic Dazed And Confused.
"But now they're together, you see how difficult it is to manoeuvre through life with one other person and be on the same track. It's tough."
To pull off this atypical storyline which, like the first two films, takes place over a single day and is characterised by long shots of Jesse and Celine simply walking or sitting as they have marathon debates about everything from life and relationships to philosophy and art, Linklater knew he needed actors who could be more than just mouthpieces for his thoughts.
To help him create their banter - which is by turns witty, caustic, intellectual and silly - he cast two actors who went on to become writers themselves: Hawke with the novels The Hottest State (1996) and Ash Wednesday (2002) and Delpy with the two romantic comedies that she both wrote and directed, 2 Days In Paris (2007) and 2 Days In New York (2012).
The pair and Linklater collaborated closely on the Before films, with all three sharing screenwriting credits for Before Midnight and Before Sunset. Before Sunset earned them a joint Oscar nomination for Best Adapted Screenplay.
Delpy is quick to point out, however, that those long chatty takes are fiendishly difficult to shoot. And even though Celine and Jesse's chats appear to flow freely from topic to topic, "nothing in those scenes is improvised".
The scene at the beginning of the latest movie, for example - a single take of a conversation lasting almost 15 minutes - "sets up the whole movie", she says. "So everything is scripted. You can't add one line."
The memory of it is enough to give her a "flashback of anxiety", she says, with a laugh. "It's such a challenge, it hurts my head just to tell you about it."
Linklater says he would not try this with most actors. "But I know what these guys can do as performers because we've worked a lot over the years.
"And I think it was important for people who feel like they know Jesse and Celine to just be dropped in with them - in the reality of that lengthy take, with no editing, no telling you who to look at, no emphasis - so that you can feel like you're hanging out with them. That was the vibe that the film needed right off the bat."
The director was inspired by a similar encounter he had in 1989, when he met a woman in a shop and spent the next six hours, from midnight till dawn, just walking, talking and flirting with her.
Those long shots of Celine and Jesse doing the same are one reason why these films feel so intimate and natural, says Delpy.
"By not using those technical tricks - the chop, cut, close-up, medium shot, etcetera - he basically breaks clean of the language of typical film-making and, in a way, you feel like you're witnessing something that's not a film and it makes it feel very real."
"It's really hard," she says of these extended exchanges. "You are rarely asked to do that as actors, maybe once in every 10 films. And here we have big chunks and it can sound really boring if you're not super-duper natural when you're saying it.
"That's the hardest thing to do - to tell a story on camera without sounding boring, and finding the right tone, like you're really telling a story to someone you care for."
Linklater also wanted to test the boundaries of conventional storytelling, not just in terms of the structure of the films - which Hawke says "would get you thrown out of any decent screenwriting class in America" - but also in daring to create characters that might come off as, God forbid, unlikable.
"We do have this very small audience in mind," says Linklater. "So when we get to a crossroad and think, 'Oh well, cinema and storytelling narrative language says that this plus this equals an unlikable character', we go, 'Oh, maybe our audience - whoever that is - might appreciate that we go there on this subject."
Still, he never thought the first two films would do as well as they did, amassing stellar reviews and a devoted following despite their small budgets and limited releases.
Some fans have come up to Delpy and Linklater over the years to thank them for what these movies have done for their love lives.
The actress says: "A lot of people have come up to me and said, 'Oh, I fell in love with my boyfriend watching this film', 'We reconnected after five years because I saw Before Sunset', or 'He decided to call me when he saw it'.
"So we are responsible for a few children and marriages."
Before Midnight opened in Singapore on Thursday.
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