What is the name of the person Bart becomes a father and friend to?
Bart, a used car salesman in the midst of realizing his life is a failure, kills the obnoxious parents of what he believes is an abused 12-year-old brat, Melissa, as he tries to close them in the sale of the only car he has left on his lot. Despite witnessing this, Melissa refuses to shoot him when he hands her the gun and tells her he would "understand", then promises to take her cross-country to Texas to live with her only surviving family, Aunt Betty, in what he believes will be a final act of salvation - one last good deed. With his two salesmen, Dwight and Derrick in tow, they take flight from the murders and one Quinton Bendick, Bart's sadistic mentor, former friend and creditor, and become an odd family with Derrick serving as a father figure for Bart and Dwight, while Bart becomes father and friend to this tough, intelligent 12-year-old. 
At a river bed Bart dances a 70's line dance with Melissa in front of the car that contains the bodies of her parents, just before he dumps it into a river. In an accident of fate, the group discovers Melissa's prowess with a gun, and Bart teaches her about life, wearing the white hat, doing the right thing, and Annie Oakley, whom she comes to idolize. 
Bart and Melissa team up to do a trade to a small town used car salesman as Melissa comes to Bart's aid for the first time. A small town bartender matches bravado with Derrick with disastrous results for Dwight when he hits him in the head with a beer mug, wounding him severely.
Stopping in a lounge Bart dances with Melissa again, and as she begins to feel her youth and freedom we watch her through Bart's not so parental eyes. In a seedy small-town motel it becomes apparent Dwight's head wound is too severe to ignore, and Derrick and Dwight leave the group to take Dwight to a hospital.
Melissa