These days, Japanese films are based on everything from novels to game apps, but Yuya Ishii’s “The Tokyo Night Sky Is Always the Densest Shade of Blue,” which premiered at the Berlin Film Festival this year, is a rare feature inspired by a book of poetry. Its author, Tahi Saihate, is only 31 but has been publishing prolifically since 2004.

Ishii, 33, is also a former wunderkind who grabbed local and international attention a decade ago with a flurry of raucous indie films. He then shifted to more conventional subjects and treatments in “The Great Passage” (2013), “Our Family” (2014) and “The Vancouver Asahi” (2014).

This new film, scripted by Ishii, marks his return to the indie end of the spectrum, if with a glossier style than his early work. Also, the scrappiness has given way to a moody romanticism, mainly expressed in the poetic musings of the heroine, Mika (Shizuka Ishibashi). The setting, however, is the gritty one of hospitals, “girls bars” and construction sites where the characters’ dreams of love, and their very existences, are threatened — or extinguished.

The realism — with stand-ins for Japan’s working poor, elderly and migrants illustrating various social ills — and the poetic love story, with coincidence piled on incredible coincidence, make for an ungainly fit. And the dialogue, much of which seems to have been lifted from Saihate’s work, often sounds like nothing anyone would actually say, unless they were on stage at a poetry recital.

Despite this, the central story of two wounded outsiders finding each other is told with a spiky eloquence and lyricism. True, the heroine is an overgrown adolescent who seethes with resentment about her past and the unfairness of life, but beneath the prickly exterior is a sensitive girl who was traumatized at a young age and, as irritating as she may be, deserves sympathy.

Mika is a hospital nurse, whose duties include apologizing to survivors after an untimely death. In the evening she pulls a second shift at a girls bar — an establishment where men chat up the women pouring their drinks. Why she needs to work two stressful jobs is not immediately explained, but we sense a rebel chafing against society’s limits and expectations.

Next we meet Shinji (Sosuke Ikematsu), a young misfit who works as a day laborer and is given to bursts of verbal loghorrea that annoy his stoic coworker Tomoyuki (Ryuhei Matsuda). Nonetheless, Shinji, Tomoyuki and two other laborers, the middle-aged Iwashita (Tetsushi Tanaka) and the easy-going Andres (Paul Magsalin), go together to Mika’s bar. This is not the first time Shinji and Mika have locked eyes, though — and it won’t be the last.

Their many run-ins set up expectations for romantic complications, but we eventually learn why Mika is always bristling with anger and suspicion. We also find out that Shinji has a secret — and is not the harmless flake he first appears to be.

As the pasts of both intrude, the story whirls about like leaves caught on a breeze — though it stops short of swirling down into the darkness Mika is forever expecting.

I see that I’m becoming poetic myself. Time to stop with a prosaic suggestion: Buy the book.