The thriller Black Rock starts out with three gal pals headed to a remote Maine island for a weekend of camping and bonding. But then a group of hunters arrives to prey on more than small game. After an attempted sexual assault, all-out warfare breaks out. ''The girls start to turn primal,'' says Katie Aselton (FX's The League), who directed the film even as she was on screen plunging into chilly water, being stripped naked, and clawing through the dirt for weapons. ''It's 43 degrees, you have to take those wet clothes off if you're going to survive, and you're vulnerable,'' she says. ''That is true animal instinct.'' Girl power has never been so chilling.