The older sister next door: Shall I give it to you?

Jinwoo and Yura, the older sister next door, have lived in the same neighborhood since childhood. One day, Yura tells Jin-woo that there is no one at her house in the evening and asks her to buy her alcohol and come to play. That evening, while having a drink together, Yura, who got drunk, attacks Jinwoo. The next day, Jin-woo's friend, Kyung-min, has nowhere to go with her girlfriend, so she talks to Jin-woo and goes to Yura's house to play, and the four men and women gather together to drink. Drunk Kyung-min enters Yura's room, and Jin-woo sees it and enters the room with Mi-jeong, her friend's girlfriend...