APT (released as 9:56 in Singapore) is a 2006 South Korean horror film, directed by Ahn Byeong-ki and starring Ko So-young. It is based on a comic by Kang Full.

Plot summary

Se-jin, a lonely department store employee, moves into a high-rise apartment building. One day she notices that the lights in the windows of the building opposite all start to mysteriously flicker at exactly 9:56pm. She begins to suspect that these occurrences are somehow linked to a series of suspicious deaths in the neighbourhood.

Trivia

Scenes of this movie are used in the music video of "Chizuru" performed by a Japanese band called "The GazettE".