In the TV series, Sunja meets Koh Hansu, a fish broker who often frequents Sunja's town of Busan. Hansu is a respectable man, and both fishermen and merchants take him very seriously. Sunja and Hansu first lock eyes at her village's market, but they don't get to know each other until Hansu intervenes when Japanese boys attempt to sexually assault her at the market.
After this event, Sunja and Hansu form a relationship, and Hansu opens up to Sunja about his poor upbringing, his dreams, and life in general. He's characterized as tender and loving at first, but after Sunja reveals she's pregnant, he acts cold and controlling of her.
The book paints a different picture of Hansu. Rather than their relationship blossoming from an emotional connection, it's formed by Hansu's persistent pursuit of Sunja. The book presents Hansu as a man who's aware of his power and influence over others. He uses this to woo Sunja, pressuring her into caving into his romantic advances.