Down on his luck true-crime writer Ellison Oswalt (Ethan Hawke) has decided that too chase the brass ring of success then one most put it all on the line. But Ellison had no idea that what "putting it all on the line" entailed.
"Sinister" opens with footage from a Super 8 camera depicting a family of four standing beneath a tree with hoods over their heads and nooses around their necks as an unseen figure saws through a limb that is acting as a counterweight. The branch lets go and hangs the foursome
Months later, enter washed-up true-crime writer Ellison Oswalt as he moves his family into the murdered family's home. Only Ellison, however, is aware that the house was the crime scene. Ellison intends to use the murders as the basis for his new book, in hopes that his research will turn up the fate of the family's fifth member, a little girl named Stephanie who disappeared following the murders.
Ellison finds a box in the attic that contains a projector and several reels of Standard 8 mm footage that are each labeled as innocent home movies. Watching the films, Ellison discovers that they are snuff movies depicting families being murdered in various ways: having their throats slit in bed (Sleepy Time '98), being burnt to death in a car (BBQ '79), being drowned in their pool (Pool Party '66), being run over by a lawn mower (Lawn Work '86), and the hanging that opened the movie (Family Hanging Out '11). The drowning film proves especially disturbing for Ellison after he notices the face of a demonic figure watching the drownings from the bottom of the pool. Ellison eventually finds the figure observing the murders in each of the films, along with a strange painted symbol; inspecting the lid of the box containing the films, Ellison discovers childish drawings depicting the murders, along with crude sketches of the demonic figure, identified as "Mr. Boogie." Consulting a local deputy (James Ransone), Ellison discovers that the murders depicted in the films took place at different times, beginning in the 1960s, and in different cities across the country. He also learns that the families were all drugged before being killed; and that a child from each family went missing following every murder. The deputy refers Ellison to a local professor, Jonas (Vincent D'Onofrio), whose expertise is the occult and demonic phenomena, to decipher the symbol in the films. Jonas tells Ellison that the symbols are that of a pagan Sumerian deity named Bughuul (Nick King), who would kill entire families so that he could take their children into his realm and consume their souls
