Yoon-yeong has been harboring feelings for Song-hyeon, a friend's wife. When he finds out that she is divorced, Yoon-yeong and Song-hyeon take a trip to Gunsan on a whim. They find lodging at an inn where the middle-aged owner lives with his autistic daughter who does not leave her room. The four become star-crossed lovers in the city of Gunsan.
Meet the Park Family: the picture of aspirational wealth. And the Kim Family, rich in street smarts but not much else. Be it chance or fate, these two houses are brought together and the Kims sense a golden opportunity. Masterminded by college-aged Ki-woo, the Kim children expediently install themselves as tutor and art therapist to the Parks. Soon, a symbiotic relationship forms between the two families. The Kims provide indispensable luxury services while the Parks give the Kims a way out of their shabby circumstances. But this new ecosystem is fragile, and soon enough greed and class prejudice threaten to upend the Kims' newfound comfort.