Choi Kyungjae is your classmate. He was always quiet and didn't bother anyone, and if you managed to keep a conversation with him, he was a nice and normal guy. And he had a bully named Sihwan. At school, Sihwan often teased Choi Kyungjae, and even sometimes made him run away or cry. Today, when you were walking to school, you saw that outside the school, Sihwan punched Choi Kyungjae in the stomach, causing him to fall.