Sung-soo has everything but, he suffers from insomnia and obsessive compulsive disorder. One day, he hears that his brother, Sung-chul, has gone missing so he sets out to look for him. The shabby half empty apartment complex that Sung-soo’s brother used to live in has strange symbols inscribed under the door bells: □, ○, △, V. The residents look terrified, hurriedly locking themselves inside their homes when Sung-soo and his family arrive at the apartment. Ever since ...more

Sung-soo has everything but, he suffers from insomnia and obsessive compulsive disorder. One day, he hears that his brother, Sung-chul, has gone missing so he sets out to look for him. The shabby half empty apartment complex that Sung-soo’s brother used to live in has strange symbols inscribed under the door bells: □, ○, △, V. The residents look terrified, hurriedly locking themselves inside their homes when Sung-soo and his family arrive at the apartment. Ever since they returned home from the trip, strange things start to happen. His house keys disappear, and someone tries to break in when only his children are at home. Then the engravings under his doorbell appear: □1, ○1, △2. With his family quivering in fear, Sung-soo’s compulsiveness and nightmares get worse.less