Tracey Stokes (Nick Cannon), the son of a deceased policeman, is a scrappy rookie bike officer in Santa Monica, itching to be involved in solving bigger crimes. The suspicious death of a student attending a posh Beverly Hills high school has him going undercover, much to the disapproving dismay of his senior officer (Cheech Marin), to get to the bottom of things. What Tracey uncovers is a raft of car theft and drug dealing masterminded by the seemingly least likely of suspects.

The premise of The Underclassman is so familiar as to be groan-inducing, but the happy surprise is that it goes down very easily, and makes for agreeable summer light entertainment. Director Marcos Siega directs at an appealingly brisk pace, the action scenes are smoothly shot and edited, BT's music cooks and, while the script is no great shakes-and, despite its wannabe hip flavor, uses now-ancient ghetto terminology like "boo yah"-it suffices and doesn't get too much in the way of the attractively diverse cast. Blacks, Hispanics, Asians and whites are all mixed in this together, making it a refreshingly equal-opportunity caper, benefiting from all the various energies.

Cannon bears some resemblance to Marlon Wayans but is infinitely more appealing, substituting a laid-back charm and real dramatic acting chops for Wayans' unbearably overwrought shenanigans. He has a real performance rhythm going with all the other actors, especially Marin (world-weary and very good) and Roselyn Sanchez, who, having survived the disastrous Boat Trip and Chasing Papi, makes a fit, smart and sexy romantic accomplice for him, as his slightly older Spanish instructor. (She herself rather resembles Sandra Bullock, but in all the good ways, with her own very real spark; who knows, she may even inspire some youthful viewer interest in foreign languages.) Lovely Kelly Hu, whose character is unethnically called Brooks, has a nice part as a fellow police officer, and has her own comic rapport with an inescapably flatulent cop. Shawn Ashmore does well in the role of a deeply conflicted big man on campus. Johnny Lewis (Quintuplets, Raise Your Voice), one of Hollywood's most ingratiating young actors, is both comic and touching as one of those genre ubiquities: the hapless rich white kid who wants to be black. Hugh Bonneville munches scenery happily as the school's pompous Brit principal.

-David Noh