Joan Jett is the protagonist of The Runaways a biopic of the real life band. She is portrayed by Kristen Stewart who played Bella Swan, Snow White and Lisa (Zathura).
she is first seen in a clothes store looking for a leather jacket which she purchases using a bag full of a variety of dollars and coins. Over the course of the film she meets producer Kim Flowley and they start putting together a girl band. They recruit drummer Sandy West, Lita Ford, Cherie Currie and Robin Robbins (former bassist turned attorney Jacqueline Fuchs didn't give permission to use her actual name).
The Runaways is formed and sign a record deal with Mercury Records and success follows them. They travel to Japan and after one one of their concerts band member Lita gets jealous and throws a magazine at Cherie since the article focuses on just Cherie. Cherie becomes confused due to fact since she thought the article would be about all of them. They argue and over enthusiastic fans try to ambush them, causing the girls to run and leave the building. The Publicity gets worse when Cherie overdoses and Joan defends her making Lita furious. The band breaks up. Eventually Joan starts her own Band called Joan Jett and the blackhearts.
Years ago by and while Joan is doing interviews on a radio station, Cherie who is working at a bakery calls in and they have an awkward reunion. Cherie listens to Joan's new songs and smiles knowing that her former band member and friend is doing well.