In a small town in Massachusetts, four friends, Wren, Hallie, Chloe and Katie summon the Slender Man. A week later, Katie disappears and the other three girls go to her house to investigate for clues. The three discover that Katie had been involved in the occult and that she wanted the Slender Man to take her. The three girls decide to make contact with the Slender Man in an attempt to get Katie back in exchange for something else.

Wren, who has researched Slender Man mythology, warns Hallie and Chloe not to open their eyes while the three are making contact with the Slender Man for fear of death or madness. Chloe panics, opens her eyes and comes face to face with the Slender Man. Sometime later, the Slender Man enters Chloe’s house and drives her insane..

In a small town in Massachusetts, a group of friends, fascinated by the internet lore of the Slender Man, attempt to prove that he doesn’t actually exist – until one of them mysteriously goes missing.