“Step Up 2 the Streets” is an earnest sequel to the 2006 cornball musical drama “Step Up,” mixing new characters into the original’s setting, the neighborhoods surrounding the Maryland School of the Arts in Baltimore.

Like its predecessor, this follow-up takes place in a gritty neighborhood, has a white lead, posits a universe where racial and class differences are minor obstacles to fun and pretends its clichés aren’t clichés.

The heroine of this one is Andie (Briana Evigan), an orphaned girl and a member of the 410, a notorious crew that stages musical pranks in public places and competes in dance contests at a club called the Streets. Andie auditions for admission to the school and gets in on the good word of its star dancer, the handsome, blond Chase (Robert Hoffman), who saw her dance at the club. Andie’s commitment to her new school gets her kicked out of her old crew, but no matter. She forms a new crew with Chase, who fantasizes about winning the grand prize in a contest at the Streets.

When Andie and Chase, both of whom are white, hold forth on the values of the Streets and barge into the club demanding that its mostly nonwhite patrons give them respect and a shot at the title, the movie is writing socially aware checks that its trite, fake-inspirational story can’t cash. This willfully clueless attitude about race and class — factors examined in the recent, vastly superior “How She Move” — is irritating.

But there are saving graces, notably exuberant musical sequences (the best of which depicts couples salsa-dancing at a backyard barbecue) and a likable supporting cast, including Adam G. Sevani as Moose, a diminutive, goofy but preternaturally confident dancer who might be the baddest nerd in movie history.