The death of Chae-heon, a boss at work, who he has been watching for a long time while hiding his affection. Chae-ul, who tried to hold on by pretending to be timid, collapses. However, a familiar face suddenly appears in the blurred vision with tears. Chae Heon is back from death. But his memories, his eyes, and even his body temperature have changed...? What is the identity of the beast in Chaeheon's perfect shell? One man and one beast. The story of two men living together.