The Battle of Westview was the final showdown between Agatha Harkness and Scarlet Witch, as well as a clash between Vision and White Vision in Westview, New Jersey. The battle resolved the Westview Anomaly, releasing the townsfolk from Maximoff's thrall.
The Westview Anomaly
Two weeks since the Battle of Earth, a grieving Wanda Maximoff visited S.W.O.R.D. Headquarters in an attempt to recover the deceased Vision's remains for a proper funeral. She met with Director Tyler Hayward, who led her towards the operating room where the synthezoid was being dismantled, much to her horror. Hayward explained to Maximoff that due to S.W.O.R.D.'s legal and ethical obligations, as well as the valuation of Vision's corpse, such a recovery was not possible. In addition, he hinted that not many people possess the power to resurrect the dead. Maximoff barged her way into the operating room to inspect her lover's corpse, but found no signs of life. She then left the facility without further incident.
Driving into Westview, New Jersey, Maximoff arrived at a plot Vision had purchased prior to his death, intending for the two to live together. Finding only ruined foundations, she viewed the property deed, which contained a handwritten note: "To grow old in. V." Ravaged with grief, Maximoff collapsed to the ground, inadvertently releasing colossal waves of chaos magic which would construct the house, enthrall Westview and transmute it into a '50s suburb, and form a new Vision out of thin air.
Maximoff would enjoy an idyllic suburban life with this Vision as the stars of the period sitcom WandaVision, influenced by the sitcoms she watched growing up in Sokovia. She soon produced twin sons named Billy and Tommy Maximoff.
Tyler Hayward's Campaign
The FBI and S.W.O.R.D. began investigating the sudden disappearance of the Westview populous. Captain Monica Rambeau was sent by Director Hayward to investigate the Anomaly with Jimmy Woo, but was absorbed into the town when she got too close to the forcefield surrounding the town perimeter.
In response, S.W.O.R.D. assembled a base outside the town. Dr. Darcy Lewis' equipment was able to detect broadcast signals intertwined with the CMBR found at the site, allowing the agency to tap into the WandaVision sitcom to monitor Maximoff. When Rambeau re-emerged from Westview, her first-person intel was collected, leading Hayward to determine Maximoff as the sole culprit of the Anomaly, or as Lewis called it, the "Hex". He proceeded the give the order to terminate her via drone, but this failed as the drone was destroyed, and Maximoff soon emerged from the Anomaly to warn Hayward not to disturb her reality again.
Hayward soon had Rambeau, Woo, and Lewis expelled from the base for defending his target, but they were able to escape captivity and go into hiding. When the chaos magic Vision approached the barrier, Hayward sent S.W.O.R.D. over to observe. Vision indeed crossed the barrier into the real world, but soon began to disintegrate. Lewis attempted to intervene, but Agent Monti handcuffed her to a vehicle. To save her husband, Maximoff expanded the Westview perimeter, absorbing Vision and Lewis simultaneously.
Hayward managed to escape the expansion, assembling another base eight miles from Westview. There, S.W.O.R.D. siphoned chaos energy from the drone Maximoff had destroyed to restore the original body of the Vision, reprogramming him to serve as their sentient weapon to kill Maximoff and her Vision.
Born from Chaos
Rambeau and Woo, having also escaped the expansion, met up with Major Aly Goodner, who had delivered a heavily-armored S.W.O.R.D. rover theorized to be able to penetrate the barrier safely. As Rambeau attempted to enter Westview again, the density of the barrier matched the rover, leading it to become subjected to the reality overwrite. Rambeau escaped, but in a final attempt to reach out to Maximoff, used her body to breach the barrier herself, exposing her to the bombardment of radiation inside the barrier that had rewritten her cells before. She emerged into Westview with an altered physique, giving her superhuman powers.
Meanwhile, Maximoff's neighbor "Agnes" lured her into a gothic lair located beneath her home, revealing herself as Agatha Harkness, a witch who infiltrated the Westview Anomaly in an effort to determine where Maximoff's power originated. Harkness forced her to relive her past, and upon doing so, identified Maximoff as the chaos magic-wielding Scarlet Witch.
In an effort to steal Wanda Maximoff's chaos magic for herself, Agatha Harkness held her twin children Billy and Tommy hostage, attempting to strike a bargain with her false reality. However, Wanda attacked Harkness instead, and ordered Billy and Tommy in the house to shield themselves. Wanda was soon approached by S.W.O.R.D.'s White Vision; mistaking him for her husband, she attempted to embrace the original Vision, but found her skull being cracked instead. Her Vision arrived and knocked the white alternate into an RV that exploded, but he was left unfazed. While the two Visions ascended to the skies to duel, Maximoff flew away to confront Harkness.
Meanwhile, Monica Rambeau was trapped in Harkness' house by "Pietro Maximoff". Discovering a property document, she learned that Harkness did not own the property, but rather "Pietro", who's real name is Ralph Bohner. Rambeau discovered an enchanted necklace on Bohner and, upon removing it from his neck, freed him from his enthrallment.
A World Reawakened
At the Westview town square, Harkness confronted Maximoff with information from the Darkhold that regards to the Scarlet Witch: that she is forged into existence with a destiny to destroy the world, possessing power that surpasses even the Sorcerer Supreme-- that same power not bound to a coven or incantation. Maximoff attempted to deny any correlation to legend, but to emotionally manipulate her, Harkness released the residents of Westview from their enthrallment.
As the enthralled were unwillingly able to observe Maximoff's trauma and grief, they immediately recognized their captor, and swarmed her with pleas for their release and questions regarding their loved ones. Maximoff however became overwhelmed with guilt and soon burst into anguish, accidentally releasing another wave of magic that formed bands around their necks, which began to suffocate them. She hastily reversed the spell, but as Maximoff finally realized the corrosive extent of her influence on Westview, Harkness taunted her, on the notion that "heroes do not torture people". Casting a beam into the sky, Maximoff began to destroy the Anomaly, prompting everyone around her to flee.
Meanwhile, at the S.W.O.R.D. retreat, Tyler Hayward prepared to send S.W.O.R.D. into Westview. In the skies above, Chaos Vision was dueling White Vision when the former began to disintegrate, allowing the White to overpower him with his laser. Sent to the ground, Vision saw his wife in the process of destroying the Hex, while a disintegrating Billy and Tommy arrived at the town centre, who had detected their mother's outburst. Horrified, Wanda subsequently stopped the process, saving her family from death.
As the Maximoff family reunited and embraced each other, Harkness fired a blast of magic at them, prompting Wanda to shield it with her chaos magic. Doing so, however, allowed Harkness to absorb more of the life essence and chaos energy from her. S.W.O.R.D. and White Vision soon descended into the town square, leaving the family to split up to tackle their enemies: Chaos Vision resumed his duel with White Vision and Wanda pursued Harkness, while Billy and Tommy remained to confront the military.
Using Billy's telekinesis and Tommy's super-speed, the troops were soon disarmed, which led Hayward to emerge from his vehicle and shoot at the children, intending to kill them. Monica Rambeau rushed in and blocked all but one of the bullets with the body-- Billy's telekinesis powers was able to stop the last bullet. Hayward attempted to flee, but was stopped by Darcy Lewis, ramming his vehicle with her food truck.
The two Visions ended up in the local public library, where they subsequently halted fighting to converse peacefully about the odd nature regarding their existence. Chaos Vision brought up the Ship of Theseus thought experiment to White Vision, and the two synthezoids used themselves in the analogy: as Chaos was one of inorganic origin generated as a replacement to the original, White was the one reassembled, free of the "rot". Chaos Vision suggested that the "rot" were the memories rooted in the original databanks of the Spectral, who recognized that they were being kept away from him for the sake of a more easily-controllable sentient weapon. White allowed Chaos to access his databanks to restore his memories and eradicate S.W.O.R.D.'s programming, before recognizing himself as the one true Vision and flying away from Westview.
Wanda Maximoff's Apex
While her Vision reunited with their children, Wanda Maximoff ambushed Harkness and subjected her to a hallucination, revisiting her 1693 trial and failed execution. The corpses of the coven victims began to reanimate, and although Maximoff expected them to torment their killer, they immediately recognized her as the Scarlet Witch. She was bound to the stake in place of Harkness, who offered her bargain once more: give up the chaos magic, and Maximoff's new family can continue to exist.
Leaving the hallucination, Maximoff began to repeatedly blast the malevolent witch with her chaos magic, allowing her to absorb it. Vision attempted to help his wife, but a wall summoned by her kept him away. As she obtained more chaos energy, Harkness began to celebrate her apparent victory, informing the weakened Maximoff that their deal would be permanent. However, she soon discovered that her dark magic would no longer work, only to find out that Maximoff's actions were merely a distraction for her to cast protection runes on the walls of the Hex. The powerless witch could do nothing but witness Maximoff absorb her magical essence; as her powers reached an apex, Wanda fully morphed into the Scarlet Witch.
A defeated Harkness would later be enthralled by the Scarlet Witch as her sitcom character "Agnes", to entrap her within Westview.
As parts of Westview lay damaged as a result of the conflict, Scarlet Witch and Vision conceded that it was time to move on from the town. The Maximoff family returned home for the final time, while the Hex began to retract, revering its reality overwrites across town and slowly restoring Westview to normal.
Knowing that she'll lose her family once the Hex disappears, Wanda bid goodbye to Billy and Tommy as they were being tucked into bed, thanking them both for choosing her to be their mother. Anticipating his deletion, Vision approached his wife to ask her what he really is, learning that he is part of the Mind Stone that is bound to her. As the two kissed, Vision reflected on his past incarnations: as a voice, then a body, before becoming a realized memory; he expressed wonder at what his next form will become. The couple tearfully embraced each other one final time and confessed their undying love, vowing to see each other again someday.
The Westview Anomaly then ceased to exist, as did Vision, Billy, and Tommy. The Scarlet Witch returned to the town square, where amidst the sea of scowls cast at her by her former thralls, she found Monica Rambeau, who did not share the sentiment, instead expressing empathy towards Maximoff's sacrifices. Maximoff in turn apologized to Rambeau for her actions, and while she admitted at being inexperienced with her powers, she was however determined to master them.
As the FBI and local police arrived, Maximoff bid Rambeau farewell before flying away from Westview, taking the Darkhold with her. She observed the welcome sign one last time before departing. Jimmy Woo emerged and took over the Westview investigation from Tyler Hayward, who was escorted out in handcuffs.