This low-budget haunted prison movie has weak acting and inept camerawork and it looks cheap and ugly, but it's still entertaining, unpredictable and creepy. The soundtrack is a cavalcade of unsettling electronic hums and howls that give the proceedings a deeply nightmarish atmosphere even when nothing much is happening. Leslie Ann Valenza, an actress whose enormous lips appear locked in a permanent frown, searches for her missing sister in a backwoods region near an abandoned prison. Written on one wall inside the filthy old structure is a weird symbol that causes anybody who even looks at it to go completely insane and become instantly possessed by an ancient evil locust-god. The possessed parties turn violent and are difficult to kill, making the film hover close to traditional zombie rampage cinema. There are continuity errors and only a few isolated examples of photography that isn't lousy, but the mood is effectively ominous, the pacing is good and the bloody gore effects are as convincing as anything in much more expensive features. Some of the gore sequences are quite intense and don't pull any punches. The demon-possesed characters and bloody convict ghosts are authentically scary. A major weakness is that, in spite of the title and numerous references to swarms of locusts in the dialogue, we never see so much as one single locust buzzing around. This curious omission of apparently important visual content would've been a lot less noticeable if they had given the film a title like, oh, I dunno, maybe "PRISON OF THE DEMONS" or "LOST SOULS BEHIND BARS" or "THE GIRL WHO'S ALL LIPS VS. THE DEVIL", or some such thing that wasn't a specific reference to a plague of locusts. It's also a bit distracting when we are told that a police deputy can't get his jeep any nearer than a mile from the prison because of the overgrown terrain and then the next group of shots offer plenty of good looks at a perfectly clean road that runs right up to the building. Still, as I said, the whole thing is really creepy and the meager story at least keeps moving right along. For all its flaws, I enjoyed it much more than HOSTEL or SEE NO EVIL, similar-minded gore movies released by major studios which cost a heck of a lot more to produce. I'd definitely watch another horror movie made by these same people. If that sounds like a "Just-Barely-A-Thumbs-Up" rating for THE 8TH PLAGUE, well, that's what I'm giving it.