Bong Joon Ho’s “Parasite” begins as a comedy about a con job with a hint of rom-com possibilities, then morphs into a horror movie before ending as a tragedy with social commentary. One wishes one understood Korean to hear all the linguistic nuances of politeness, but the actors convey the issues of class and even personal vulnerabilities that lead to failure. Making its world premiere at the Cannes Film Festival, “Parasite” was the first Korean film to win the Palme d’Or.

Set in South Korea, the film opens on the Kim family — father, mother, son and daughter — which is on the lower economic end of the technology boom. They live in a basement with a row of windows without curtains that open at street level. From the socks hanging out to dry in what little sunlight enters, you get the idea no one’s really attempting to better the view. A drunken neighbor staggers and urinates in plain sight, but the Kims are impotent to stop the display. Their biggest concern is whether they can steal wi-fi service for their phones from a neighbor or a nearby business. Together, they work at folding boxes for a pizza place, but even there their careless ways come under criticism.

Ki-woo (Choi Woo Shik) has failed four times to pass the college entrance exams, the only way to assure a better life. Yet that’s his main selling point when his old chum, Min-hyuk (Park Seo Joon), visits him with a gift — a scholar’s rock meant to bring the family financial prosperity. Min-hyuk has also come with a job offer: tutoring the spoiled daughter of a rich family. Min-hyuk fears his college classmates might want to move in on the good-looking girl and Min-hyuk intends to make her his girlfriend when he returns from a year studying in the US. Min-hyuk advises Ki-woo to lie about his credentials. After all, the girl, Da-hye (Jung Ziso), needs to pass the exams and Ki-woo has more experience taking the tests than the more successful candidates.

With the help of his artistic and computer graphic arts savvy sister, Ki-jung (Park So Dam), Ki-woo acquires forged documents but finds, as Min-hyuk advised, the mother, Mrs. Park (Cho Yeo Jeong) is “simple.” Less simple, is the housekeeper, Moon-gwang (Lee Jung Eun), who is often charged with caring for the wild younger son, Da-song (Jung Hyun Jun).

Mrs. Park is proud of Da-song’s primitive artwork. Ki-woo presents his sister, Choong-sook, as a very exclusive art instructor with a background in art therapy and art psychology and renames her Jessica. Da-song’s waywardness is linked to a shock he had when he was younger, something that his mother only will allude to, but is revealed to the audience much later.

The con game doesn’t stop there. Eventually both mother Chung-sook (Chang Hyae Jin) and father, Ki-taek (Song Kang Ho) will become part of the Park household, supplanting both the housekeeper and the chauffeur, respectively. We don’t see the chauffeur again, but on a weekend when the Parks go on an overnight camping trip, the Kim family has unwisely decided to stage family pig-out in the posh Park home. Moon-gwang returns, insisting she left something in the basement. What that something is will shock and surprise the Kim family, but also transition us into both a comedy and a karmic horror tragedy. Much of this hinges on Mr. Park (Lee Sun Kyun), a young CEO of a global IT company and his pet peeve: “I can’t stand people who cross the line.” Mr. Park is talking about his servants, but forgets that he, too, crosses the line while blinded by his sense of entitlement.

Bong (“Okja”) has stated that the Kims were not parasites from the start, but as they wormed their way into the lives of the privileged, circumstances “pushed them to the edge of a precipice.” “Parasite” is “a comedy without clowns” and “a tragedy without villains.” Expect some blood and a surprisingly poignant ending.

In Korean with English subtitles.

“Parasite” opens at the Pasadena Arclight tonight, Oct. 17, and at the Laemmle Claremont 5 and Laemmle Glendale on Nov. 1.