A serial killer Soo-chul (Jung Kyung-ho (actor, born 1983)) has been terrorizing a neighborhood in Seoul, and in the span of 6 months, 10 people have disappeared without a trace. He uses a manhole to trap his victims. His latest abductee is Soo-jung (Kim Sae-ron), a 14-year-old girl, and her older sister Yeon-seo (Jung Yu-mi (actress born 1983)) is desperate to find her before time runs out.