Being a young actress in Hollywood can be a horror show even for performers who achieve something akin to stardom a condition thats temporary for all too many of them. Consider the case of Mischa Barton. She was a sizzling property in 2003 upon the arrival of The O.C., a trendy series whose buzzability tended to obscure its fairly modest viewership numbers. Barton extricated herself from the show before it petered out circa 2007, with her character, Marissa Cooper, going out in prime-time soap style via a fatal car crash. But shes been unable to parlay her TV notoriety into big-screen success, and now shes stuck accepting parts in formula cheese like Homecoming, which begins its local run tonight. The flick is yet another variation on the obsessed-psycho-girlfriend formula, with Barton playing a stereotypically deranged nutball who runs over her romantic rival and then holds her hostage, Misery-style. Irony alert: The kidnapped character is portrayed by Jessica Stroup, currently a regular on the rebooted 90210. Stroup ought to look upon Bartons career trajectory with far more terror than this tired flick manages to stir.