Journalist Ji-Won (Ha Ji-Won) receives threatening phone calls from a man involved in an underage sex scandal that she has exposed, so she retreats to an empty house owned by her best friend Ho-Jung (Kim Yoo-Mi) and gets her phone number changed. When Ho-Jung's daughter Young-Ju (Eun Seo-Woo) starts to behave like someone possessed after answering Ji-Won's ringing phone, Ji-Won, who is herself experiencing strange visions, begins investigating the deadly history of the phone number's previous owners, and follows a trail leading to secrets buried uncomfortably close to home.
