Brian and Christine have never been close. Now that she's disappeared, and he's changing into something monstrous, people are starting to talk. People like the police, for instance. And a strange boy who claims to be Christine's long-dead brother. Also, people are starting to shoot. At Brian. A lot. It's annoying, because all he really wants to do is find Christine and maybe ask her out or profess his undying love or something. So yeah. If he has to become an evil entity of mythical power in order to get the girl? So be it.