Erebus centers around the Gorham House, a mysterious old hotel with a torrid history of violent occult activity, as well as supernatural, and paranormal. Seeking to document the hotel for a new book, Samantha and Benny, journey to investigate the hotel, learning of its terrifying history along the way by relaying three horrifying tales of its previous owners.

A group of young people meet for dinner. After an argument, two of the guests engage in a parody of a knife fight. The end of that fight is the beginning of another tragedy, older and deeper, that is deposited in those knives.