Sang-eun is a beautiful 20-year-old girl who is mentally challenged. One day she happens to meet a boy and deludes herself to think he's a beast under the vicious spell.

Following the brutal rape and murder of his 16-year-old daughter, Sang-hyeon stumbles into an ever-widening conspiracy of rage, revenge, and murder.

BJ Yagwang and PD Park broadcast a live stream themed around horror on AfreecaTV. They look for more provocative and fearful material for their program. One day, they receive a video which contains a female high school student disappearing. In the video, right before she disappears, the female school student was calling a ghost and playing hide-and-(go-)seek alone. While broadcasting live on AfreecaTV, BJ Yagwang goes to the abandoned building where the female school student went missing.

Ah-young, a grown orphan with government aid cut off, starts working as a nanny for Young-chae, a single mother who works at a bar to make ends meet.