The first season focused on the Harmon family who moves from Boston to Los Angeles to start with a clean slate, and establish in an long-standing manor house and have no notion that his previous housemates did not find rest after death.
The second season tells basically different story. The action comes around the newspaperwoman, who came in a mental health institution for the criminal lunatic with a view to shoot a journalistic story about the new arrived maniac "Bloody face", who kills randomized women pitiless.
Third season is about witches' sabbath disguised as an elite pansionate for "gifted" girl which try to protect the last representative of this species from extinction.
The plot of the fourth season circle around one of the last "Freak show" in the 1950s.