Slender Man tells the story of a tall, thin, horrifying figure with unnaturally long arms and a featureless face, who is reputed to be responsible for the haunting and disappearance of countless children and teens.

In 1967 Los Angeles, a widowed mother and her daughters add a new stunt to bolster their seance scam business, inviting an evil presence into their home.

In the forests of the Pacific Northwest, a father devoted to raising his six kids with a rigorous physical and intellectual education is forced to leave his paradise and enter the world, challenging his idea of what it means to be a parent.