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.

A surrogate mom for a couple becomes dangerously obsessed with the soon-to-be father.

After an all-night adventure, Quentin's lifelong crush, Margo, disappears, leaving behind clues that Quentin and his friends follow on the journey of a lifetime.