The Butterfly Sign: Human Error is the second chapter of the first person detective video game in which we are playing as a sole survivor of a serious terrorist attack. Protagonist is the only witness of the incident and his fate depends on his memories. That’s why he goes in for a desperate measure: he takes the experimental medication called “Rammex”, which immerses him in the depths of his mind and makes him accurately recollect a chain of events, which had happened. While wandering through his own memories, the protagonist has to look for evidences and learn bits and pieces to find the guilty persons…

Kidnapped and taken to an unfamiliar location, nine people find themselves forced to participate in a diabolical Nonary Game by an enigmatic mastermind called Zero. Why were they there? Why were they chosen to put their lives on the line as part of a dangerous life and death game? Who can be trusted? Tensions rise as the situation becomes more and more dire, and the nine strangers must figure out how to escape before they wind up dead.