At the beginning of the series, Sam is a college student doing a research project on the urban legend known as the Slender Man. Her and her girlfriend, Cass, head to various locations until their friend helping them, Alison, is found murdered. Sam is then blackmailed by an unknown person, leading her to a morgue where she is possessed by a mysterious evil entity. The entity then tortures Cass, saying it was supposed to possess her rather than Sam.