It’s ironic that “Poetry” would open with the image of a dead body floating near the film’s superimposed title, but the best of world cinema subverts viewers’ expectations. Director Lee Chang-dong (“Secret Sunshine”) does that through the entirety of this Cannes-blessed work from South Korea, even before it begins: Doesn’t a drama about a woman with early-onset Alzheimer’s and who longs to write verse sound terribly dull and boring?

And yet it’s quite the opposite. “Poetry” is one of the more compelling films you’re likely to see this year. It plays Friday through Sunday at the Oklahoma City Museum of Art.

Yun Jeong-hie embodies the character of Mija, a senior citizen working part-time as a maid/caretaker for a lonely, elderly man whose body no longer responds to his wishes, post-stroke. Combined with a pittance of a government subsidy, she gets by, enabling her (barely) to raise her ungrateful snob of a teenage grandson (newcomer Lee Da-wit).

Mija slowly realizes that her inability to remember certain words and phrases in simple conversation — bleach, wallet, bus terminal — represent small steps toward inevitable dementia. She’s drawn to poetry readings to appreciate words while she can, but try as she might, is unable to craft any poems herself beyond a title.

But “Poetry” is not “about” writing. It’s about all the things that the kind, old woman cannot change. Functions of her brain are one thing; a shocking, terrible crime is another. I dare not spoil it, allowing you to experience and process the news as Mija does. Needless to say, it takes her crumbling world and shakes it violently.

Absent from the screen for almost two decades before taking this role, Jeong-hie delivers a remarkable performance. While she won an award for it in Asia, she lost several more, yet it’s difficult to believe any actress could have delivered anything better that year. She so disappears into Mija that one forgets her character is not real. Jeong-hie not being known on these shores is a benefit to the film’s power, whereas a recognizable actress might detract from it.

Chang-dong goes for the slow-burn approach over the course of “Poetry,” although he arguably could have shaved several minutes off the running time of two hours and 19 minutes by nixing a few of the poems read in full by other characters. His often-handheld direction — not shaky-cam, thankfully — emphasizes the piece’s intimacy of the piece, and his last few scenes together pack quite an emotional punch. The ending will haunt viewers for quite some time.