Josh Schwartz and team will have young fans of The O.C. guessing throughout the summer what will happen next. In a surprise ending on the season finale, one of the show's stars is no longer with us. Marissa, played by Mischa Barton, a top 10 female celeb on the Campus Trends Top Ten List, was killed in a car crash to close out the season last night. It was rumored that the 20 year old Barton was planning on leaving the show after this season given some of her other movie deals in the works including "Guilty Pleasures," due out in 2007. She also is a spokesmodel for Neutrogena, the number one skin care brand among teens and a clothing model for bebe. Fans of the show need not to worry too much, since it looks like Schwartz and team has already set up Mischa's younger sister Kaitlin, played by Willa Holland, to step up as problem teen number one next season.