Young Mother 4 (2016)

Woo-jin, who is a repeater of college entrance exam, and Taek-sik's friend, Kang-hee come and visit Woo-jin's hometown on a small island. Woo-jin's mom, Hyeon-sook operates a small sashimi restaurant and a bed and breakfast to make a living on the island. Although Hyeon-sook has sex with Bong-seong, she rejects his proposals. One day, Woo-jin is terribly shocked to accidentally see his mom Hyeon-sook and Bong-seong having sex.