‘Black Flies’ Review: Sean Penn and Tye Sheridan Are Paramedics Cruising Through the Inferno in a Drama That Thinks It’s More Real Than It Is

“Black Flies,” as staged with maximum overwrought hand-held sensationalism by the French director Jean-Stéphane Sauvaire, has no plot at all. It’s just one lacerating if-it-bleeds-it-leads set piece after another.