"Everybody is crazy except me. But is it a misfortune to be sane in a crazy world?"

For thirty years, "Mood Disorder" has plagued humanity - but Chang Mo sees what others can't: emotional cysts growing inside people like parasites. When they burst, their hosts become Emotional Monsters - supernatural predators that feed on human emotions, invisible to normal eyes.

In this hidden ecosystem, emotions have become currency. Monsters devour feelings - and each other - for power. Psychiatric hospitals have become containment zones. Mysterious factions wage shadow wars. And while rational people still exist, Chang Mo is different.

He doesn't just stay rational - he houses Rationality itself as his Emotional Monster. Guided by a ghost entity with its own monster, he's caught between two worlds: the sane who can't see the truth, and the infected who want to consume him.

When logic itself becomes your monster, what does that make you?