At first glance it’s just another entry in the series of delayed Blackboard Jungle spin-offs in which a principled teacherhere, ironically, a CIA mercenary (Tom Berenger)gains respect from a bunch of rowdy inner-city kids, in this case while substituting for his girlfriend (Diane Venora). But vying with this plotline, and ultimately overtaking it, are some kick-ass action sequences deriving from the fact that the principal is running a drug business out of the Miami school in question, in collusion with its leading gang. The results are lively if periodically silly; it’s too bad more use wasn’t made of the powerhouse Venora. With Ernie Hudson, Glenn Plummer, Richard Brooks, Marc Anthony, and Raymond Cruz; directed by Robert Mandel from a script by Roy Frumkes, Rocco Simonelli, and Alan Ormsby. (JR)