There is far more to the plot of Lee Chang-dong’s “Oasis” than initially meets the eye. The opening hour of the movie appears to be a rather bland and generic take on a melodrama with an unlikely match, between an ex-con Hong Jong-du (Sol Kyung-du) and Han Gong-du (Moon So-ri), who suffers from cerebral palsy. Fortunately, the romantic plot is later nuanced by a more layered focus on social issues and tensions within the families of both of the main characters.

We meet Jong-du a mere couple of hours after his release from a prison. He did time for killing a man in a hit-and-run, but shows lack of remorse for the deed. His comeback isn’t welcome by the family. A sister-in-law admits to him bluntly: “with you out of the way I felt good about life”. With no money in his pocket, lack of...