What might “Brief Encounter” look like if rewritten for the YA crowd? An answer is provided by Ry Russo-Young’s “The Sun Is Also A Star,” adapted from a book by Nicola Yoon, whose “Everything, Everything” made for a slushy weepie a couple of years ago. (One wonders whether Yoon chose the title to make people think of “The Fault In Our Stars,” hoping to piggy-back on one of the genre’s biggest hits.)

The plot of what’s for the most part a two-hander is awfully thin. Natasha (Yara Shahidi) is an undocumented young Jamaican scheduled, along with her parents (Gbenga Akinnagabe and Miriam A. Hyman) and younger brother, to be deported the very next day. She intends to make a final plea with the immigration service, but all a sympathetic worker there can do is to refer her to a lawyer friend (revealed in time as John Leguizamo).

Meanwhile Korean-American Daniel Bae (Charles Melton) is being pressured by his parents (Keong Sim and Cathy Shim) to go to Dartmouth and become a doctor, though he wants only to be a poet. He’s scheduled to meet with an alumnus for an interview.

The two strangers are joined after both wind up at Grand Central Station, where Daniel, who’s been people-watching from the rafters with his buddy Omar (Camrus Johnson), is struck by the fact that she’s wearing a jacket with the words “Deus Ex Machina” on it, a phrase he’d been toying with earlier in the morning. A complete romantic, he takes this as a sign they’re destined to be together, and after he saves her from being run over by a speeding car that has just forced an unlucky bicyclist off the road (keep that in mind for inclusion among the movie’s catalogue of coincidences), indicates as much.

But Natasha, a science-loving rationalist who loves studying the constellations (her hero is Carl Sagan), dismisses Daniel’s emotional dream as ludicrous; she thinks that love is nonsense, since its existence can’t be scientifically proven. Still, since they both have time to kill before their appointments, they agree to spend some of it together, Daniel arguing that he can get her to fall in love with him over the course of the day and Natasha scoffing at the idea. Who do you suppose will turn out to be right?

Their adventure mostly involves walking around the city—a lot of the running-time is devoted to woozily-rendered establishing montages of neighborhoods and tourist sites—though they do take the opportunity to stop off at a planetarium and what appears to be a private karaoke room (during which Russo-Young inserts a dreamy “what if?” montage of their married life together), and have a brief snuggle. They also visit Daniel’s dad and his surly older brother Charlie (Jake Choi) at the family shop—which sells black hair products, of all things (triggering what amounts to a documentary-style history lesson on how Koreans have come to dominate the wig trade!). As if to balance things, there will also be a scene with Natasha’s parents.

Without spoiling things overmuch, suffice it to say that matters wind up in that lawyer’s office, thanks to yet another coincidence. But the movie isn’t satisfied with that: it adds a postscript that piles another absurdity on what we’re already witnessed.

Shahidi and Melton are, of course, extremely attractive young people whose appearance will probably make the tween hearts in the audience beat faster. They’re not terribly good actors, posing more than performing, but that won’t really be a concern to the target viewers. Nobody else matters much, with even Leguizamo looking ill-at-ease; but Choi stands out for his truly abrasive turn. It’s not his fault, though; as written Charlie is such an odd character, not just jealous of his brother but positively nasty toward him (until he isn’t, of course), that he seems to have come from another movie.

The other major character in “The Sun Is Also a Star” is New York City. Indeed, at times the movie feels like a virtual travelogue, and cinematographer Autumn Durald Arkapaw swoons over the images of the Big Apple as much as he does the beaming faces of the leads (he favors intense close-ups); there are so many of both clichés that they become positively oppressive. It takes little imagination to conclude that though the picture isn’t all that long, editor Joe Landauer could still have improved it with further shortening. The overbearing score—by Herdis Stefansdottir, with plenty of pop tunes added to the mix—adds to the sense of heaviness.

“The Sun Is Also a Star” is an awfully annoying movie, a tearjerker that’s more jerky than tear-inducing. But it has the singular virtue of making you appreciate Richard Linklater’s “Before Sunrise” (and its two sequels) all the more. It might also make you think that it could be improved by adopting the technique of Linklater’s “Slacker,” quickly moving from the couple to somebody they pass on the street, then from that person to another, and so on. That would have been more interesting than following Natasha and Daniel around for a full hundred minutes, cityscapes or no.