Phone(폰, Pon) is a 2002 South Korean horror film directed and written by Ahn Byeong-ki and starring Ha Ji-Won and Kim Yu-Mi . The film is a complex and disturbing love story that involves possession and ghosts.

A young, frightened woman runs into an elevator. Her cell phone rings, the elevator stops, and the lights flicker. She screams to be left alone, and claws at the walls.

A young journalist, Ji-won has exposed an underage sex scandal. Her editor Ho-jeong warns her to keep a low profile until the men implicated can be tried. In this vein, the journalist purchases a cell phone with an unregistered phone number, and accepts an offer by the editor and her sister's husband Chang-hoon to move into their unused new house in order to keep a low profile for a few days. Ji-won begins to receive mysterious and disturbing phone calls. One of these calls is answered by the editor's daughter, Yeong-ju, who begins to act strangely afterwards and seems to develop an Electra complex .

The journalist examines the call records and by chance discovers that those who previously had her number have all died under mysterious circumstances (the girl in the elevator from the opening scene was one of these previous owners). The mysterious phone calls to Ji-won continue; she can decipher that they are from a female voice who is screeching about a man with whom she is very angry, but she does not know who or why.

Ji-won learns that the first number holder was a high school girl Jin-hie who went mysteriously missing. By talking to her friends, Ji-won finds out that this girl was madly in love with a man, whom she refused to name to her friends. All the while, Yeong-ju becomes more aggressive toward her mother and makes romantic advances toward her father.

Ji-won discovers that was Jin-hie was having an affair with Chang-hoon (whose favorite piece of music is Moonlight Sonata) through Jin-hie's diary.

Ji-won went back to her place to find that her laptop showing the same number again (Jin-hie's number) and her cell phone was ringing. She answered her phone and screamed while holding her ears. She tries to pluck off the power cable of her laptop from the socket only to find that the socket is connected to a bundle of hairs. She pulls the hair and the wall starts to crumble and a body behind the wall is uncovered. Ji-won uncoveres the face of the body and is shocked to find that it is Jin-hie's.

We see a flashback on how Ho-jeong found out about her husband's scandal. After she found the cell phone that Jin-hie gave him, she lured Jin-hie to the park at night and brought her to her house while her husband went on a business trip. There, Ho-jeong asked Jin-hie to abort her pregnancy but Jin-hie refused and insulted Ho-jeong about her infertility.

Jin-hie becomes angry and attempts to strangle Ho-jeong, but Ho-jeong manages to push her away, down the stairs. Jin-hie's cell phone rings, and Ho-jeong tries to pick up the phone, but is surprised when Jin-hie suddenly stands up and walks towards her. Cornered, Ho-jeong picks up a small statue and hits Jin-hie in the head. Ho-jeong tries to take the phone away from the now dead Jin-hie, but she holds it tightly, probably due to cadaveric spasm .

Back in the present, in the same location,during the final confrontation, Ho-jeong tells Ji-won about her jealousy toward fertile women and told her to keep her mouth shut. Ho-jeong then gave Ji-won an electric shock that caused her to become unconscious. She then ties Ji-Won up, blind folds her, then gags her with duct tape.

Chang-hoon is lying in a bathtub filled with water with a piece of broken mirror stabbed on a deep cut on his wrist. From the reflection of the broken mirror, we saw Ho-jeong who then went to get accelerant . She went back to the room where Ji-won was and poured the accelerant on Ji-won and Jin-hie. She was preparing to torch Ji-won and Jin-hie's corpse, but the lighter kept blowing off. When she managed to keep the lighter lit up, Jin-hie's body started to move within the walls. Ho-jeong was shocked and fell on the floor while Ji-won regained her consciousness and tried to break free.

In the morning Ji-won woke up and her hand was freed. She saw Ho-jeong lying dead behind the curtain but Jin-hie's body remained planted on the wall.

Ji-won throws the troublesome mobile phone off a cliff. As the phone enters the water it begins to ring.