In a world where humans and demons coexist invisibly, a woman named Yurine and her servant, the Karas, maintain order. However, as humans forget the demons' existence, an old Karas rebels, creating mechanized demons to attack. Otoha inherits Karas powers, joining Yurine to stop this threat. Meanwhile, police officers Sagisaka and Kure investigate the chaos caused by Eko's demons, uncovering a dark prophecy that could change their city forever.