Investigator Mitsuha Ashitaba loses her position after a wrongful arrest while pursuing an anonymous, mobile crime ring, but her sense of justice drives her to continue the undercover operation alone. It is all a trap: the gang injects her with a muscle relaxant, leaving her unable to move, then subjects her to a brutal group assault meant to break both body and mind. She clings to her pride, yet the relentless abuse gradually wears down her resistance until her body's unwanted pleasure overwhelms her resolve in an explosive finale.