Wasted on the Young (2010)

The film follows Darren (Oliver Ackland), a nice-enough high schooler who spends most of his time around computers and homework. He is the polar opposite of stepbrother Zack (Alex Russell), whose priority is maintaining a reputation as Mr. Popular. Things take a sinister turn when the shy Xandrie (Adelaide Clemens, a dead ringer for Michelle Williams) is invited to one of Zack's house parties and goes missing for almost a week afterwards. By the time she returns, the school is rife with rumours surrounding her disappearance, and Darren, suspecting his stepbrother and his nasty bunch of friends, decides to find out the truth and punish those responsible.