Wishing Stairs

Wishing Stairs ( also known as Whispering Corridors 3: Wishing Stairs) is a 2003 South Korean horror film. It is the third installment of the "Whispering Corridors" film series set in girls high schools, but, as with all films in the series, is unrelated to the others; apart from a song being sung in one scene that is a pivotal plot in "Voice".
Plot.
Yun Jin-sung (Song Ji-hyo) and Kim So-hee (Park Han-byul) are best friends studying ballet at an all-girls art school. However, their friendship turns sour when they find themselves competing for a single spot in a Russian ballet school. Jin-sung learns from an odd student named Eom Hye-ju (Jo An) of an old legend that if a person climbs the twenty eight steps leading up to the school's dormitory and finds a twenty ninth step, then a fox spirit will grant that person's wish. Curious, Jin-sung climbs the stairs and comes across the twenty ninth, happily wishing to gain the spot. To her surprise and anger, So-hee is selected instead. Jin-sung declares her hatred toward her and accidentally sends So-hee down a flight of stairs during a scuffle. So-hee is left unconsciousness and hospitalized.
Jin-sung learns that So-hee is no longer able to study ballet due to her injuries from the fall. She tries to apologize, but receives no reply and leaves guilty. The next day, she learns that So-hee has committed suicide. As the fight between the two was witnessed by several others, Jin-sung is now looked down upon by the students, who believe that she intentionally pushed So-hee out of jealousy. Jin-sung's wish comes true and she gets the spot for the ballet school but her fellow students treat her coldly.
Affected by So-hee's death, as she was the only one to treat her with kindness, Hye-ju attempts to keep So-hee's belongings for herself, but is ridiculed for it, mainly by Han Yun-ji. She climbs the steps and wishes for So-hee to come back. So-hee returns as a twisted spirit who possesses Hye-ju. The possessed Hye-ju confronts Yun-ji for bullying her and stabs her to death. Jin-Sung encounters Hye-ju, who tries to convince her that she is So-hee. The spirit of So-hee makes Hye-ju light a match, leaving the troubled girl to perish in flames.
While Jin-sung is preparing to leave for the ballet school, she is haunted by So-hee. Unable to endure it, she tries to climb the stairs again in order to wish her away. Before she can reach the top, So-hee appears and holds her as Jin-sung confesses that she didn't hate her and simply wanted to be happy. Believing that Jin-sung does not love her as much she does, So-hee crushes Jin-sung's stomach with her arms, killing her, then vanishes.
Some time later, a new girl moves into the dorm room that Jin-sung once occupied. A picture with Jin-sung and So-hee on it is seen on the floor. In the photo, So-hee's irises disappear, implying that she still remains.
Notes.
The film itself seems to mirror the ballet Giselle, which girls in the film are studying, as well as drawing upon the classic short story The Monkey's Paw, with So-hee as Giselle, and Jin-sung as Albrecht. Unhappy with always having to play the "prince" to So-hee's princess, Jin-sung betrays So-hee, which in turn leads to So-hee being crippled and commits suicide after her friend Jin-sung confesses she has hated her all along. When So-hee's spirit is wished back, Jin-sung is haunted by So-hee's ghost, the love she once felt for her friend warped by Jin-sung's hurtful actions.
As in the two previous movies, this film has strong themes of friendship, betrayal, and the taboo of lesbian affairs in an all-girls school.