When an idea is carefully nurtured, it grows and takes on a life of its own. But what happens when a destructive idea settles in the mind? It may be merely imperceptible at first, just a microscopic germ. The malevolent idea feeds on the person's mind. It multiplies. It devours everything around it. Everything good that fought against it. Willpower, empathy, kindness, felicity. All of the good healthy qualities of the person disappear as they are devoured by its insatiable appetite. At this point, the parasite has outgrown the host's capacity for healthy coexistence. And that's when everything explodes.
Triada - Season 1 Episode 1