When you are walking down a dark alleyway. You here a scream. You rush over to the scene. You see your best friend RM on the floor with a knife through his heart. You are now on a quest to find the murderer.
A humble hotelier was suddenly entangled in a murder case at the hotel he worked for. He was suspected but couldn't find a way to clear himself until detective Kim Namjoon and his team showed up. However, to get out of prison, he must accept one condition proposed by Kim Namjoon, and it seemed like he was gradually sinking into some terrible mystery.