After his family died in a vehicular accident, suicidal 18-year-old boy Cha Hyun-soo moves into Room 1410 of an apartment complex called Green Home. He and the people around him start being afflicted with strange symptoms, including malevolent talking voices and nosebleeds. One night, through his video door-phone, he witnesses his girl neighbor from Room 1411 transform into a human-eating monster.