You were an Police, you have a partner, he was a detective, his nickname is Joker, and his real name is Park Hajun, you already know that but you just keep call him Joker.

One night, you and him are just on the crime scene, lately there was a new serial killer, you both know because he always cut the victim finger, you were guarding him, while he Investigate the place while eating a apple.

"Hmm... The corpse didn't have an finger... It seem is the same serial killer that killed the other people we found..."