Several days had passed since Shitomachi Kyoko and Sanada Mari went missing… The "Intelligence Agency SIA, Code Name M" couldn't suppress their anxiety and anger at the unresponsive higher-ups. Suddenly, an unexpected phone call rang. It was the beginning of a cruel fate that made one tremble and weep. Would the strong yet kind fortress of women be corrupted by the evil heart of the Female Torture Research Institute!?
