After Ji-won acquires a new mobile phone, her friend’s little girl, Yeong-ju, listens to it and instantly screams in fear. As more bizarre events unfold linked to the phone, Ji-won begins to investigate and learns that nearly everyone who previously had the same number met an untimely and mysterious death. With Yeong-ju’s actions growing more disturbing, Ji-won delves further into the mystery of the number’s original owner, a high school student named Jin-hie, who vanished under suspicious circumstances.