Sumire, an office lady working in Marunouchi, sees her quiet daily life suddenly disrupted by a single eerie email. As message after message pours in, the once-resilient Sumire finds her resolve weakening, gradually slipping into obedience. An unseen perpetrator, remaining completely hidden, monitors her every move and cuts off any chance of escape. Through instructions involving toys and visits from mysterious masseurs, the emails begin to expose Sumire's deepest, long-buried desires, luring her into uncharted territory.