Following the delightful and crafty enviro-monster thriller The Host, director Bong Joon-ho could have easily directed anything from a Host sequel to a period costume drama and succeeded handily.  Like many of his Korean New Wave contemporaries, Bong traffics in stellar performances, magnificent visuals and camerawork, and twists that liven up time-worn story models.  It’s no surprise that his work is extremely successful at home, while translating only modestly in the United States.  With Mother, the director leverages a standard whodunit format with Kim Hye-ja’s searing performance as a woman who refuses to let her mentally challenged adult son go to prison for murder.

An herbalist and unlicensed acupuncturist, Mother (who is nameless throughout the film) works in a small shop, keeping a constant watch over Do-joon, whose behavioral issues range from forgetfulness to near-Autistic impairment.  Do-joon hangs around in the streets with his frequently mean-spirited and violent friend Jin-tae, and when he is hit by a passing car, it is Jin-tae who suggests they chase it down.  After attacking a group of businessmen on a nearby golf course, Do-joon takes the blame for some of Jin-tae’s handiwork when questioned by the police.  But the next day, when a local girl with a bad reputation is found brutally murdered on a rooftop, Do-joon is immediately arrested for the crime based on witnesses’ accounts that he was the last one to be seen in her company.

Mother attempts to make headway with the local police, with whom she has cultivated a relationship over the years, as well as a high-priced attorney who, at first, treats her case as an after-thought.  But when it is clear she cannot rely on them, she begins investigating what happened on her own, seeking out background on the victim, Jin-tae, his girlfriend and a local junk dealer.  What she discovers, and what she is capable of doing to protect her son, creates considerable tension while building a somewhat tentative air of sympathy for her and Do-joon.  But every time she seems closer to an answer, a new secret comes to the surface, with more damning repercussions for them both.

Kim Hye-ja is miraculous as the beleaguered Mother, whose defensive strategies range from compassionate to desperate to savage.  Mother’s age and doggedness make her a uniquely entertaining, if uncertain, sleuth.  And Bong enjoys his moments of stretched-out, quiet tension: a water bottle spills and its contents flow slowly toward a sleeping culprit’s hand; a re-tracing of the victim’s final moments in the dark of night is eerily matter-of-fact.  Hong Kyung-pyo’s (Tae Guk Gi, Save The Green Planet!) cinematography is by turns deceptively pedestrian and alluring; a shot of Mother swaying dreamily in a vast field stays with you long after the film’s end.

The film is not without a couple of rather prominent flaws.  There is an awkward intimacy between Do-joon and Mother that is reflected in the first act of the film, and it manifests itself as something creepy and untoward, which makes sympathy for the characters difficult until her investigation has gotten into full swing.  The endgame feels far too simplistic for the amount of red-herrings dumped in the middle, making for an almost cheap answer to the film’s primary mystery.  But the jagged edges of each progressive development manage to make the whole ride worthwhile.

As a thriller, Mother takes some time getting up to speed, but once in full detective mode, it is a supremely satisfying piece of work.  But the film is unmatched with the flawless range of its lead actress, and the assuredness of its director.