In May 2014, two 12-year-old girls lured a classmate into the Wisconsin woods and stabbed her nineteen times, telling police afterward that they did it to prove themselves to Slender Man, a faceless figure invented on internet forums and passed around through fan fiction and creepypasta. The film follows the case through police interrogation footage, courtroom hearings, and interviews with the attackers' parents, who struggle to explain how their daughters moved from fantasy to violence. Psychologists and online-culture researchers weigh in on how a crowdsourced horror character spread across message boards and video sites until some young readers stopped treating it as fiction. The documentary also tracks the surviving victim's recovery and the legal fight over whether the girls should be tried as adults. It resists easy answers about mental illness, parenting, or the internet itself, instead laying out the timeline and letting the contradictions between the girls' accounts and their families' assumptions stand on their own.