Scream scripter Kevin Williamson sure wants to teach something in his directorial debut (titled Killing Mrs. Tingle before the Littleton massacre made high-school homicide déclassé). Something about integrity, or morality, or being true to oneself. But this effort is not true to Williamson's own penchant for trashy, cynical teen-slasher violence, and the result is a stodgy hodge-podge of sleaze and self-righteousness.

Giving the picture backbone is Helen Mirren in the title role, a basilisk-like history teacher whose only apparent pleasure for the past 20 years has been flunking the best and brightest of Grandsboro High School -- such as Leigh Ann Watson (Katie Holmes), an A student from the other side of the tracks whom Tingle accuses of cheating. With her pals, dumb but hunky Luke (Barry Watson) and trampy wanna-be actress Jo Lynn (Marisa Coughlin, diverting in her re-creation of a scene from The Exorcist), Leigh Ann winds up holding Tingle hostage and unsure of what to do next. Blackmail? A bolt between the eyes from a crossbow? Williamson is similarly bewildered, so Tingle finds itself longing for the glib moralism of a latter-day John Hughes while itching for the cheap thrills, bad taste, and crass plagiarism of a Scream 3. You just can't teach a new dog old tricks.