Brick employs a simply brilliant movie high concept: It’s a classic film-noir detective story set in a contemporary high school. Joseph Gordon-Levitt plays an intelligent teen loner who has been recently dumped by his social-climbing girlfriend. He’s still infatuated, of course, so when she disappears he sets out to find her by winding his way through his school’s stratum of nerds and druggies, flirts and jocks. Once you register what Brick is trying to do, the movie never comes across as a gimmick. The endless halls of lockers stand in nicely for dark, film-noir alleys, while the rapid-fire lingo — spit out just as Humphrey Bogart did in The Maltese Falcon — seems a natural fit. Like those gumshoes of old, teenagers have a language all their own. Writer-director Rian Johnson’s triumph is not that he applies noir style to a teen setting, but that he uses it to give teen concerns — love, drugs, friendship — a fresh and vital forum.