In the small town of Holston, Oregon sits an abandoned mansion called the Holston house. The house is eerily well-maintained, considering that it has sat empty for many years. There are rumors that the Holston's youngest child, Mary, walks the halls looking for someone to play with her. It is Halloween night and a group of teenagers, including a girl named Emily, decide to break into the house. The friends are not particularly nice to one another; there is light disagreement and taunting throughout. Emily reveals that she doesn't like many of the group members, besides having a slight crush on Elisa. When they enter the property they immediately split up, with one group member, Elisa, staying by the gate in order to graffiti it. She is the first to bump into Mary, who is appalled by her littering (Elisa spits her gum onto the ground) and foul language. Mary's disapproval of Elisa's language leads her to inflict violence on Elisa. When another group member, Aiko, splits off to smash a window with a baseball bat, similar events transpire with Mary. After being fed-up by the two friends that she is stuck with, Emily goes off to find Aiko. When she encounters Aiko's unresponsive but breathing body, she reflects on her own motivations for embarking on the night of pranks, thinking about how she thought it would bond the group and give her a sense of belonging. Mary watches Emily holding Aiko, the first "trick-or-treater" that she doesn't see as coming to hurt the house or break things. An indeterminate time later, Mary now calls Emily "sister." Emily's friends are exiting the house. It is revealed that Emily has agreed to stay in the house with Mary on the condition that her friends could leave. The friends have now been cured of their desire for mischief. Emily hopes that she will be able to warn other naughty kids away. Nothing in the house can decay except for Emily's body.