“Deadly Detention” (* out of four) was a deadly dull horror thriller about five high-school brats (Sarah Davenport, Alex Frnka, Henry Zaga, Coy Stewart, and Jennifer Robyn Jacobs) who are serving detention when they find themselves being stalked by an unseen murderer with no way out because the school is on lockdown. Potentially fun cross between “Friday The 13th” and “The Breakfast Club” is undone by irritating characters and slapdash production. Final plot twist is particularly dumb. You keep waiting for John Bender to show up and laugh these clowns off the screen.