Someone Behind You

Did You Know?

• The film is based on the manhwa It's Two People by Kang Kyung-ok.
• It was released in America at the 2009 After Dark Horrorfest film festival with the title Voices.
• Filming started on March 30 in Gwangju Gyeonggi province and completed on June 1, 2006 in Hongcheon.
• The promotion team hosted a guerilla event on August 11, 2007, where two people in bloody school makeup scared bystanders and handed out fans with the film's title.
• The film reached number one in pre-release ticket sales in 2007, but was a commercial flop.

Plot

Kim Ga-in is a South Korean student attending her aunt Jee-sun's wedding. Before the ceremony, Jee-sun is pushed from a balcony and taken to the hospital. Ga-in waits with her boyfriend, Park Hyun-joong, while her aunt recovers. They then see Jee-sun's younger sister, Jung-sun, stab her repeatedly. Jung-sun is arrested for the murder and questioned. The family believes they are under a curse that causes at least one member to die in inexplicable ways. In this case, Jung-sun was possessed and killed Jee-sun. At school, top student Jung Eun-kyung tries to kill Ga-in with scissors. During the struggle, Eun-kyung is stabbed instead and transfers to another school. That same day, Ga-in's teacher blames her for Eun-kyung's departure and attempts to kill her, but a classmate saves Ga-in.

Hong Seok-min, an odd student rumored to have killed his own father, tells Ga-in she cannot trust anyone, not even herself. She visits Jung-sun to ask about the murder. Jung-sun explains that Jee-sun's husband was her ex-boyfriend, and she wanted revenge on Jee-sun. She says an unknown force possessed her and forced her to kill. That evening, the classmate who saved her tries to kill her. Ga-in runs inside, where her mother throws knives at her. Frightened and unsafe at home, Ga-in tells her father she is leaving. He mentions a forgotten family member in another village named Hwang Dae-yong. On the bus, Ga-in meets Seok-min again, and they visit Dae-yong together.

Dae-yong recounts how he killed his wife in a jealous rage after suspecting an affair, then searched for the force that controlled him after his release from jail. After Ga-in and Seok-min return home, Dae-yong commits suicide to escape the curse. At school, Ga-in has a vision of her best friend killing her and realizes she truly cannot trust anyone. One night, she wakes to find her parents dead. It is revealed that Hyun-joong killed them. He stabs Ga-in as she tries to save her younger sister Ga-yeon, intending to set the house on fire and turn it into hell. Both sisters stab him and leave him dead as the house burns.

In the hospital, Ga-in and Ga-yeon share a room. Ga-in has nightmares and is woken by her sister. She hallucinates Ga-yeon pulling a knife from her pocket; they struggle, and the knife stabs Ga-yeon. Ga-yeon cries out, asking how Ga-in could do this to her own sister. Seok-min appears and reveals his true nature: he is the curse. Only Ga-in and the people he controls can see him. Ga-in looks at Ga-yeon and realizes it was not a knife in her pocket but a burnt family photo. Seok-min then tries to kill Ga-in. She stabs him, but in reality, she stabs herself because he is controlling her from within.

In the epilogue, a boy is verbally abused by his teacher. After the teacher leaves, Hong Seok-min appears in a new body and asks the boy if he wants help getting back at the teacher.