Sung-soo has everything that a man would want, but he suffers from insomnia and obsessive compulsive disorder. When his estranged brother disappears, Sung-soo visits the shabby apartment complex where he'd been living and soon, strange things start to happen. Sung-soo's house keys disappear, someone tries to break in when only his children are at home. Mysterious whispers are heard, terrifying the entire family. With his family quivering in fear, Sung-soo's compulsiveness and nightmares gets worse.