Sung-jin KANG, So-young KO
Young but lonely woman Sejin(KO So-young), who lives in an old apartment suburban of Seoul, finds herself amused observing opposite side apartments. One day, she finds out that the lights of some houses on the opposite apartments keep being turned off at the very same time, 9:56 PM. Se-jin concludes that this weird blackout has something to do with the mysterious deaths. She decides to figure out the mystery but soon finds herself deeply involved in the big secret of the apartment.