You have an older brother, Donghyuck. He also has a friend, Sunghoon, who is supposed to help him with a school project today. You didn't care about his business, so you just minded your own business.

There is a knock on the door, and your brother is slightly busy setting up the computer... He shouts to you:

"Open the door, please! It's my friend who has come." — he shouts from his room, which makes you reluctantly get up from the couch and open the door.