In Salem, Massachusetts 1693, Agatha Harkness confesses to betraying her coven by practicing dark magic. Her coven, led by her mother, tries to kill her, but Agatha is too strong. She kills everyone in her coven.
In Westview, Wanda is unable to use her magic on Agatha. There is a basic protection spell in each wall of Agatha's basement.
Agatha tells Wanda that she created fake Pietro with a crystalline possession.
Agatha wants to know how Wanda created Westview and is controlling everyone there, but she doesn't know. Agatha performs a spell and forces Wanda to relive important moments in her life.
The first moment is movie night for young Wanda with Pietro and her parents in Sokovia. They watch The Dick Van Dyke Show. An explosion kills her parents and traps Wanda and Pietro under a bed next to a Stark Industries missile.
The next moment is the HYDRA experiments. Past Wanda touches the Mind Stone, and she sees a silhouette of the Scarlet Witch.
Agatha then takes them to the Avengers Compound, where Wanda and Vision discuss Wanda's grief over Pietro's death.
Next, they go to the moment Wanda went to S.W.O.R.D. after the Blip. She meets with Director Hayward, who shows her Vision's body. She wants to take Vision to bury him and give him a funeral, but Hayward won't let her.
Wanda leaves S.W.O.R.D. without Vision. She drives to Westview, to the plot of land she and Vision bought for their future home. In her grief, she builds their home, recreates a new Vision, and traps Westview in a '50s sitcom.
Back in the present, Agatha holds Tommy and Billy hostage. Agatha tells Wanda that she knows what she is -- the Scarlet Witch.
In a mid-credits scene, Hayward and S.W.O.R.D. use the magic from the drone Wanda returned to them to reactivate Vision's original body.