|Name||Dr. Mia Vallens|
|Episode(s)||13.04 The Big Empty|
Dr. Mia Vallens was a grief counselor and shapeshifter operating in Madison, Wisconsin. In her youth she met a young man named Buddy, also a shapeshifter, but she become tired of the abuse and violence that Buddy enjoyed inflicting on others and herself. Mia became a grief counselor, using her shifting abilities to help bring closure to people grieving for their deceased loved ones.
After discovering that Wes Bailey and Gloria Simon are connected through being patients of Mia, Sam, Dean, and Jack visit her under the pretense of dealing with the grief of losing their mother. The three arrive at the end of her work day, however Mia agrees to see them. She explains how her program works, and when a heated exchange between Sam and Dean leads to Sam leaving the room, Sam ends up discovering Mia is a shapeshifter when he finds blood, skin, hair, and teeth in Mia's bathtub. As Mia tries to talk to Dean about his anger and how Jack looks terrified of him, Sam barges through the door, gun in hand, and warns Dean that she's a shifter. Holding Mia at gun point, Dean accuses her of killing her patients. Mia denies it, telling them she never killed anyone and has been helping people. She explains that she shifts into the person that a patient has lost so that they could see them one last time and say goodbye. She says she was volunteering at a women's shelter when one of the prior murders happened. When her alibi checks out, Mia reveals to the Winchesters she may know who is committing the murders. She shows them a picture of her past partner, Buddy, explaining how he enjoyed destroying people's lives and how she had had enough of the abuse and left him to start a new life.
As Dean and Jack check out if Mia's assistant is actually Buddy, Sam combs through her surveillance. When a man appears with an eye flare, Mia identifies him as a recent patient, Jack Driscoll, and gives Sam her car keys to check him out. When Dean and Jack arrive back at her home, Jack asks to speak with her while Dean tries to reach Sam. In the next room Jack explains how his mother died when he was born, showing Mia the video Kelly made for him and asks Mia if he could see her just once. Mia agrees and has Jack close his eyes while she shifts her form into Kelly's. When he opens his eyes, Jack begins crying and calls out "Mom" to Mia and hugs her. He tells Mia how he thinks he may be a monster, but Mia tells him it doesn't matter what he is, only what he does and that even monsters can do good in the world. After Mia changes back, Jack thanks her as Buddy, appearing as Dean, barges into the room, picks up a fire poker, and knocks Jack unconscious. After immobilizing Jack and Dean, Buddy peels off Dean's face from his body. He tells Mia he never stopped looking for her and explains once he found out what she was doing to help people, he couldn't let her continue. Buddy gives Mia a choice: she will kill Dean and Jack or be killed by him. Mia chooses to be shot, but just as Buddy is about to kill her, Sam arrives, taking his attention away from Mia. As Buddy takes a shot at Sam, Jack uses his powers to save Sam and knock Buddy away, allowing Sam to kill him.
In the aftermath Mia tells the Winchesters what Buddy did was her fault and she will deal with it, telling them she only wanted to help people. Jack assures her that she did.