Professor Xavier is inside a room. A doctor tells another doctor to bring a patient in. We see a high-level containment field open, and a girl is released. She struggles to escape, and melts the bonds that contain her. She breaks free and begins causing massive amounts of destruction. Two doctors attempt to apprehend her, but she stretches out her hands and the walls cave in. She opens the door to the room Professor Xavier has been waiting in, and approaches him with an outstretched hand.
Professor Xavier uses a psychic blast to weaken her, and knocks her to the ground. He begins to talk to the girl, Wanda,about keeping her powers under control. She tells him to get her out of the asylum, but he says that he cannot risk it. A doctor enters and tells Professor Xavier that he needs to do some additional tests on Wanda in the Radiology room. Wanda goes quietly this time.
The doctor continues to walk with Wanda, and Wanda realizes she is being kidnapped. She becomes very anxious and begins destroying things around her. The doctor opens a door, and an elderly woman begins chanting spells. Wanda becomes "at rest" and falls into the woman's arms. The doctor transforms into Mystique and goes back inside the building.
At Bayville High School, Kurt is attempting to open his locker, but to no avail. Kitty enters and aids him by phasing through his locker to retrieve his book. He thanks her, and she asks him to try one of the muffins that she made in Home-Ec class. He tries it and is disgusted. As he drops the muffin, it begins to bounce up and down.
After school, Scott asks Jean about Duncan, her boyfriend, and Jean says that Duncan is not the guy she thought he was when she first began to date him. Scott attempts to tell Jean about how he feels about her, but Duncan arrives in a flashy car and honks his horn. Jean goes to Duncan's car and leaves Scott standing there as Duncan and Jean drive away.
At the Brotherhood Boarding House, Mystique enters. All of the boys are surprised she has returned, and she throws Toad against a wall. She is angry that the boys have destroyed her house. Tabitha enters, and prepares to fight Mystique, but Pietro tells her that it is not a good idea. Tabitha decides to move out of the house. Mystique comments that Tabitha learns quickly, unlike the boys. Pietro asks where she has been all this time. She does not tell him, but declares that the X-Men are about to get knocked down a peg. She introduces Wanda, who she kidnapped from the asylum earlier. Pietro recognizes Wanda as his twin sister, and Wanda begins destroying things in the house. Lance tries to stop her by making an Earthquake, but she makes it turn around and attack him instead. She does the same thing with a blast of Slime that Toad shoots at her. Eventually, the same elderly woman from before calms Wanda with the same spell. Mystique identifies the woman as Agatha Harkness. She says that Wanda will help them because she can give Wanda revenge on her father, Magneto. Tabitha returns and leaves, claiming that there are too many women for one house. Mystique's room explodes because Tabitha put one of her explosive bombs in it.
At the Xavier Institute, Kurt is hiding from Kitty so that he won't have to try another muffin. Scott finds him upside down hanging on the light. Kurt gets down because his stomach hurts too bad. Kitty finds him and offers him another muffin. Professor Xavier calls the students and Kurt uses it as an excuse to teleport away. The muffin Kitty had given him makes a large dent in the floor. Professor Xavier tells the students that Wanda has escaped and that someone plans to use her powers against the X-Men.
Wanda is at a training session with Agatha Harkness. Her anger is far too strong to overcome in the first two sessions. Eventually, however, she overcomes this and cuts her hair. Pietro enters and she prepares to attack him. He claims he just wants to talk, and begins to talk about her life in the asylum. She says that he is just like Magneto and exits angrily. Mystique asks Pietro where his loyalties lie and he says that his loyalties lie with Mystique, not Magneto. Mystique says that she's arranging for a test of the Brotherhood's preparedness to take on the X-Men.
Professor Xavier tells the X-Men that the Brotherhood is at the mall, committing a break in. The X-Men arrive at the mall, and easily defeat all of the Brotherhood, until Wanda arrives and begins causing destruction. She makes Scott's eyebeams go haywire and attack everyone and everything but her. She reverses Evan's spikes so that they attack him. She entraps Kitty in the floor, and makes Kurt's teleportation land him outside. She reverses Jean's levitation ability and throws her across the room. Eventually Jean says that Wanda is too much to handle, but Scott wants to continue fighting. Jean is persistent and says that they must leave.
The Brotherhood is excited to have finally defeated the X-Men, and Toad comments that the victory was due to their new secret weapon: "The Scarlet Witch." Professor Xavier says that the defeat is his fault because he did not teach them how to handle a mutant like Wanda, and that victory is just as much a mockery of their character as defeat. The X-Men pay him no mind and exit angrily.