In The Good Son (Penguin, June), South Korean author Jeong presents a twisted story of murder.

Was the plot inspired by real life?

Yes. A while ago, a young man committed a crime that shocked Koreans. He had grown up wealthy, studied abroad, and returned home to lead a life of leisure. He came back from a trip to Las Vegas with huge debts and got into an argument with his parents, becoming so enraged that he stabbed them to death. He snickered with his girlfriend at his parents’ funeral. When he was arrested, he rationalized his actions and lied about everything. This kind of criminal is very rare in Korea. I thought about him constantly: how could he have done something like this? What was behind his ordinary façade? Was he crazy? Was he evil? What had triggered such violence—was it circumstance, or personality, or something from his childhood? Was this tragedy a result, in part, of our hypercompetitive society, or was it rooted in something deeper, more fundamental in humans? I spent a lot of time thinking about these questions, and I wanted to explore this topic as a writer.

Your other novels also have dark, downbeat themes. What appeals to you about writing about the dark side of human nature?

I am not that interested in ordinary, happy lives. I’m more interested in the unlucky pulled along by fate, the foolish who plummet to their demise, and those who reveal ugly, shameful selves. I like to explore the dark side of humanity. My work deals with the terrible things that create problems in our lives, like jealousy, rage, hate, greed, terror, violence; my characters are human beings pulled to the extreme. As to why I am drawn to this, Richard Dawkins says it best: “Let us understand what our own selfish genes are up to, because we may then at least have the chance to upset their designs, something that no other species has ever aspired to.”

An essay you wrote is entitled “I Dream of Fire, Always.” What do you mean by that?

That essay was about the kind of writer I want to be. I want readers to be sucked into the world of my creation and be inflamed by their emotions and experience. I want readers to stay awake all night, their hearts on fire.

How did your work as a nurse influence your writing of fiction?

I spent most of my time in the ER and the ICU, both spaces for people on the verge of death. Doing that work, I learned how to dissect a situation impartially, and I think that experience formed my view of humans as part of something larger; as merely one of the many organisms on Earth.