‘Undercurrent’: All is not lost in cathartic drama

Last year, nearly 85,000 individuals went missing in Japan. There is even a term in Japanese to describe them: jōhatsusha (evaporated people). Takahito Hara focused on the issue in his 1992 hit film “Midnight Run” as well as its two action comedy sequels. All center on an agency that helps find new lives and identities for those desperate to “evaporate.”

Rikiya Imaizumi’s film “Undercurrent” takes a darker, more introspective approach to this perennial social problem, focusing on Kanae (Yoko Maki), a woman whose husband, Satoru (Eita Nagayama), vanished two years ago for reasons she doesn’t understand. Unlike the agency clients in “Midnight Run,” he was not a debtor eager to escape snarling underworld creditors.

Instead, he was helping Kanae run the family business she had inherited from her parents: a rundown public bathhouse. A former college classmate, he had been her boyfriend for four years and then a loving husband and willing helpmate for another four. In shock from his inexplicable disappearance, she closed the bathhouse. It is open again as the film begins, but Kanae is no closer to solving the mystery that shattered her life.

Working from a script inspired by Tetsuya Toyoda’s manga series, Imaizumi has made an intricately plotted departure from his usual comic dramas about the romantic troubles of young urbanites. Also, in its drawn-out climax, “Undercurrent” resembles many Japanese murder mysteries in which a detective delivers a lengthy explanation of the case’s twists and turns.

The film’s objective, however, is less to solve a puzzle than to interrogate motives and expose lies. The effect is both cathartic, as masks drop away, and chilling, as we see that truth remains elusive in even the closest of relationships.

The casting of Maki as Kanae is puzzling at first. Often playing characters with steely inner cores in both comedies and dramas, she isn’t quite convincing as a woman who was once completely wrapped up in her husband and is still emotionally fragile from a long-ago trauma. (The expression of that trauma in a recurring dream of Kanae falling backward into the water and being strangled is mysterious and haunting, however.)

But her steeliness begins to emerge and the oppressive mood thankfully lightens when Kanae hires an oddball private detective (an on-point Lily Franky) to look into Satoru’s disappearance on the recommendation of a savvy friend (the always excellent Noriko Eguchi). The detective draws looks and responses from Kanae that are amusingly sharp, as he spins theories about Satoru that come strictly from his overactive imagination.

More central to the story is Takayuki Hori (Arata Iura), a drifter who applies for a temporary job at the bathhouse. Kanae feels he is overqualified (he is an expert on boilers), but he persists until she hires him. This awkward but intense man soon becomes essential to both the bathhouse’s operation and Kanae’s life in ways more felt than stated.

Iura has played so many characters whose still waters similarly run deep that Hori feels more like a type than anything distinctive. But he suffers from a long-unassuaged (and long-unexplained) pain that Iura expresses with quiet eloquence.

As usual with Imaizumi, the story rambles, and my patience was already wearing thin as the final confessions began. But his two leads, both thoroughly invested in their multilayered roles, swept me along to the smashing end. Strong undercurrents indeed.