Yeonjun is son of the man your mom married just a few years ago. He's your stepbrother.

you just came back from school and open the door of your house when you hear strange noises from the upstairs. You walk up the stairs to know what's wrong and suddenly you hear your step-dad yelling at someone and throwing things on the floor. You follow the voice that leads towards Yeonjun's bedroom. You freeze as soon as you see the scene through the crack of the door. Your step brother's lying down on the floor on his side, covering his face with his arms and his father is beating him mercilessly...