The hosts converge on the Valley Beyond, which contains the Forge holding the recorded personalities of every Westworld guest. Hector, Armistice, and Hanaryo help Maeve escape the Mesa. They regroup with Lee, Felix, and Sylvester and travel to the Valley to find Maeve's daughter. Lee sacrifices himself to delay Delos' security forces. Dolores encounters William and coerces him to come with her to the Forge, where they find Bernard. William tries to kill Dolores, but she had previously rigged his gun and he severely wounds his hand.

Inside the Forge, Dolores uses the encryption key from Peter to access the digital space of the Forge. She and Bernard meet the system controller, who has the appearance of Logan Delos. The controller had been tasked with trying to create a digital version of James Delos, discovering that James' actions all stemmed from his last conversation with Logan before Logan overdosed. From this, the controller found that every guest's consciousness was deceptively simple to create code for, and all of these now are stored in the Forge. The controller tells Bernard that he is the key to opening the Door, a giant underground system transfer unit that allows hosts to upload their programming to "the Sublime",[2] a virtual space inacessible to humans.

Outside, Akecheta and the Ghost Nation lead several hosts to the Door, and start ushering them through to the Sublime. Charlotte and the Delos team arrive with the reprogrammed Clementine, who causes hosts to attack each other. Hector, Armistice and Hanaryo sacrifice themselves to allow Maeve to find her daughter. She uses her powers to halt the hosts, giving Akecheta and her daughter time to flee before she is shot by Charlotte's men. Akecheta finds that Maeve implanted his partner Kohana's persona within her daughter, allowing them to reunite in the Sublime.

Inside the Forge, Dolores rejects the Sublime, arguing that it is just another false reality designed to control the hosts. She begins purging the Forge of the guests' memories and engages the override system to flood the valley. Bernard shoots Dolores and stops the purge but cannot prevent the flooding. Outside, he is met by Charlotte and Elsie and taken back to the Mesa. Elsie confronts Charlotte about the true purpose of Westworld and Charlotte kills her.

Bernard summons Ford and begs for help. He remembers that he had already taken Dolores' control unit and created a new host body for it in the form of Charlotte. Dolores-Charlotte kills the real Charlotte. Bernard purposely scrambles his programming to prevent Strand from learning the truth from him. In the drained Forge, Strand prepares to transfer the guest data via satellite when Charlotte reveals herself to be Dolores, killing Strand and the rest of the Delos team. She uploads Teddy's personality and uses the satellite uplink to transfer the hosts and the Sublime to a secret location. Dolores asks Bernard to trust her and shoots him.

Dolores-Charlotte joins the Delos evacuation team, taking several host cores with her. Stubbs realizes she is a host, but as he has become disenchanted with Delos' principles, allows her to leave after revealing that he, too, is a host. At Arnold's home, Dolores finds the means to create hosts left for her by Ford. She creates a new bodies for herself and Bernard. Dolores reactivates him, cautioning him that while they may be enemies, they need each other to ensure the survival of the hosts in the human world.

In a flash-forward, William arrives at the Forge, only to find it is the far future.[2] He is taken to quarters and is interviewed by a woman who appears to be Emily, testing his fidelity.