Midnight FM (2010)

Popular TV anchorwoman and late-night radio host Ko Sun Young prepares to work her final radio program. After this program she will prepare to take her ill daughter to America the following morning. During the radio show Sun Young receives a startling text message.
At Sun Young’s apartment, her ill daughter is being watched by Sun Young’s sister, Ah Young. Then, a man named Dong Su breaks into the apartment with alarge wrench. He knocks Ah Young unconscious, but is unable to locate Sun Young’s daughter – who is hiding in a closet. Dong Su then sends the text message to Sun Young instructing her to follow his directions and not to tell anyone.