Timeline of events: This season takes place during present day, but there are flashbacks to earlier time periods — the early '20s, '40s, '60s, '70s, '80s, and '90s.
Key moments: It's important to remember that Constance Langdon, played by Jessica Lange, states during the first season that she had four children, however, we were only introduced to three of them: Addie Langdon (Jamie Brewer), Tate Langdon (Evan Peters), and the disfigured child named Beau (Sam Kinsey) who was kept in the attic of the Murder House. The fourth child was never named, but Ryan Murphy has stated that the forthcoming season of the show — AHS: Hotel — would see us revisiting the Murder House, so it's possible that this mystery will finally be solved.
Another thing to keep in mind is that the Harmon family is from Boston, which is not too far from Briarcliff, the mental institution we were introduced to in the second season of the show.
Dr. Charles Montgomery (Matt Ross) is the original owner and the man who built the Murder House. He lived there along with his wife, Nora Montgomery (Lily Rabe), and their child, who later became known as The Infanta. This is important to note because we're introduced to the movie star Madison Montgomery (Emma Roberts) in Season 3 of AHS, which makes it plausible that there's a connection between those characters. They are also all from Los Angeles.
Halloween is important to remember because it's within the inaugural season of the series that we're introduced to the fact that the spirits of the dead are allowed to freely roam the Earth on this day. It's noteworthy because we may see some past characters reoccur because of this. This theme of the dead visiting the living has continued throughout the series.
And finally, Season 1 seemingly had a great ending with the Harmon family all dying and subsequently having their souls stuck in the Murder House for all eternity (which is cool because they all ended up together, right?), but remember that Constance was left caring for Tate's demon seed, Michael, aka the spawn of evil. Will something come of that?