The Hills is back for season 4, and the girls are beginning to make some big decisions that will set the course for the rest of their lives.While Lauren struggles to balance the tension between her roommates, Audrina and Lo, she starts dating Doug, an old flame from Laguna Beach. Meanwhile, Brody, Audrina and just about everyone else warn Lauren not to trust her new friend, Stephanie Pratt (Spencer's sister). And when Lauren makes a surprising discovery about Stephanie and Doug, she realizes that her friends might be right.Just as Audrina thinks it's time to let her boyfriend Justin go and begins dating Colin, Justin turns up the heat in their relationship, leaving her torn. Whitney rises up the ranks at People's Revolution much faster than she expected and meets a model in New York who could possibly sweep her off her feet. And Heidi deals with the consequences of moving back in with Spencer, including putting her job at risk. As if that wasn't enough, Heidi's sister Holly comes from Colorado for an indefinite visit, putting some serious pressure on her renewed relationship with Spencer.During season 4 of The Hills, life in Los Angeles only gets more complicated as friendships, relationships and loyalties are tested like never before.