Aileen Wuornos (Charlize Theron) is a mess. “I’ve been hooking since I was 13, who the fuck am I kidding, I’m a hooker.” That, and eventually the first female serial killer to be executed in America. As the film opens, she’s down to her last $5 and ready to kill herself if God doesn’t bring some light into her life. Somehow her prayers are answered: she stops at a gay bar for a quick beer or twelve and she meets Selby (Christina Ricci). A timid 18 year old whose Bible-toting folks want to cure of her lesbianism, she couldn’t be more different than the large and brash Wuornos, who’s not even gay, but something clicks between the two.

Maybe Aileen is happy to find someone who doesn’t want to use her, hurt her or make her go away, maybe Selby finds it refreshing to be with someone so impulsive and intense, maybe they just crossed paths when they both needed someone badly… Maybe this is true love. In any case, it’s very moving, especially in the way this romance blooms in such hell. “Monster” is a brutal film with scenes of beatings, rape, murder and humiliation, but when these two broken women manage to make each other feel a little happier, it’s a thing of beauty.

The way Aileen grows into a serial killer is disconcerting. Initially you can see that it’s out of desperation and in at least one case the john she murders is an evil prick that deserved nothing better, but then she keeps killing more and more guys and whatever easy motivations the movie spells out are unconvincing.

Writer-director Patty Jenkins is making her first film and sometimes it shows. She cites “Badlands” as an influence, but her appropriation of the na├»ve narration style (and even some of the score) is clumsy. Occasionally the movie veers dangerously close to ridiculous, especially in its use of cheesy ‘80s pop songs. I mean, Journey?!?

Still, “Monster” is a must-see if only for Charlize Theron’s extraordinary performance. The usually gorgeous blonde is unrecognizable as Wuornos, all bad hair, bad skin and fat ass. Yet this is more than a physical transformation, we can see all the hurt and anger in the world in her eyes, she’s like a wild beast. Then again, when she’s with Ricci, there’s vulnerability and sweetness in her and it’s heartbreaking. Theron is a mortal lock for the Best Actress Oscar and it will be entirely deserved.