Westworld's Multiple Timelines Explained
The greatest trick that Westworld season 1 played was convincing the audience that everything they were watching was taking place at roughly the same time, when actually it was taking place in three different time periods. For most of the season it appeared that William and the Man in Black were both visiting the park at the same time, when in fact they were the same man visiting the park 30 years apart. It also appeared that Bernard was having secret sessions with Dolores that he was keeping a secret from Ford, until eventually it was revealed that those scenes were also taking place decades in the past, and the man doing the interviewing was Arnold, not Bernard.
There are flashbacks to various different points in Westworld's history - like the Man in Black murdering Maeve and her daughter, a year before the show's present timeline begins. However, the bulk of the show takes place at three distinct periods of time, spanning four decades.
35 Years Ago: Arnold and Dolores
Westworld was in development for several years before eventually being open to the public, and it was during those years that Arnold and Ford's interests began to diverge. While Ford was satisfied with merely creating a simulation of consciousness - just enough to fool people - Arnold wanted to create the real thing. Dolores was Arnold's pet project, and throughout season 1 we saw snippets from Arnold's sessions with Dolores, as he tried to determine her level of self-awareness and push her towards the center of the maze.
Arnold eventually became convinced that the hosts were sentient beings, and that therefore it would be unconscionable to open the park and subject them to the horrors that guests would inflict on them. However, his attempts to convince Ford of this failed, and so Arnold made a drastic decision. He merged Dolores' conscious with a new character that he and Ford had been working on - a bloodthirsty villain called Wyatt - and had her and Teddy kill all the other hosts. He then told Dolores to kill him as well, and sat calmly in the center of the world he'd built as she shot him in the back of the head.
30 Years Ago: Dolores and William
Westworld opened despite Arnold's death, but it was thrown into financial disarray by the incident, and facing risk of possibly closure when Delos executives Logan (Ben Barnes) and William paid a visit. Shortly after his arrival in Sweetwater, William ran into Dolores and shared a brief exchange with her after picking up a can that had fallen from her horse (much later, he finds out that this is a programmed event). Logan and William set out on a quest to find an outlaw, and Dolores went home to find her family murdered by a group of bandits. She managed to kill one of them and fled the farm, and then ran into Logan and William.
From there, Dolores traveled with Logan and William, unconsciously searching for the center of the maze and a home that she had forgotten. This journey eventually brought her to Escalante, the town where she massacred her fellow hosts and killed Arnold, and she began to have flashbacks. Dolores and William were then captured by the Confederados and taken back to their camp, where Logan had risen to the rank of General. Logan tore open Dolores' stomach to show William her insides and remind him that she was just a robot. Dolores managed to escape, but presumably died and was reset shortly afterwards. Meanwhile, William took revenge by hacking every Confederado soldier in the camp to pieces, before setting out to search for Dolores on a journey of bloody self-discovery.
Present Day: Everything Else
We actually don't see very much of Dolores in the present day, but we do eventually learn that she set out to retrace her footsteps from 30 years ago, following her memories of William and believing that they were happening in the present. This journey eventually took her back to Escalante, which Ford had ordered to be dug up and reconstructed for the purposes of his new narrative. While in Escalante, she ran into the Man in Black again and he demanded that he show her the center of the maze. In a grave with her name on it, in the churchyard, Dolores found the maze puzzle that had belonged to Arnold's son and been the inspiration for his model of consciousness. It was also here that the Man in Black revealed that he was William, the man she had once loved.
Pretty much everything else that we see in season 1 also takes place at the same time as Dolores' final journey. That includes Maeve's awakening and efforts to escape, Ford's plans for a new narrative while others at Delos plot to undermine and remove him, and Bernard's efforts to uncover the secrets hidden in Westworld and find out what happened to Arnold. This is also where things will pick up in season 2, and while there will be further flashbacks, we probably won't see another full-blown multiple timeline narrative. Of course, that doesn't mean that things are going to be simple.
Westworld season 2 premieres April 22 on HBO.