Kim, a Taekwondo champion decides to give up his fighting career for good in order to take care of his daughter Sa Rang. But when an evil gambling kingpin kidnaps Sa Rang, Kim must agree to fight in a rigged boxing match in exchange for Sa Rang's freedom.
Soon after Ji-won gets a new cell phone, her friend's young daughter, Yeong-ju, puts it to her ear and immediately begins screaming in terror. When other strange things start happening in connection with the phone, Ji-Won does some investigating and discovers that of the people before her who had the same number, almost all of them died suddenly under unusual circumstances. As Yeong-ju's behavior becomes increasingly alarming, Ji-won digs deeper into the circumstances surrounding the disappearance of the number's first owner, a high school girl named Jin-hie.
