The titular tower is actually a decommissioned light house that sits upon a rock called Snape Island. We first see it when a couple of caretakers arrive on the island only to discover three brutally slain bodies. For reasons that aren't immediately obvious, the caretakers don't seem surprised by the carnage, but they are caught off guard when a crazy young woman emerges from a cupboard in the disused lighthouse (sorry, in the Tower... Of... Evilllll!) and stabs one of them to death.
The authorities quickly deduce that the crazy young woman, now hospitalised in a catatonic state, was a friend of the three dead people, and that she must have flipped out and murdered them, along with the caretaker who we know she stabbed. But the girl's family doesn't buy it, so they hire a private investigator to find out what really happened.
In order to get to Snape Island, the PI hitches a ride with a group of archaeologists who had planned to visit the island and search for ancient artefacts before all the murder and mayhem had broken out. Not surprisingly, for a movie of this genre, when the ensemble gets to the island the murder and mayhem resumes.
"I'm just saying... if you want to be taken seriously as an archaeologist, you might want to reconsider that outfit."
Tower of Evil is a strange mix of sex & violence exploitation, fine British character acting, and salacious innuendo riddled dialogue. All the archaeologists seem to have some sort of sexual history with one another and are either constantly flirting or denigrating each other, with ribald language, in between getting murdered. And when they're not getting murdered or having saucy conversations they are delivering plot-driving expository dialogue with more conviction than an actor in this kind of film has any right to.
Consistent with the uneven tone is the uneven pacing. There are moments when the film is effective and suspenseful, but there are other times when there's not much of anything really happening. The characters constantly separate, for no logical reason, making portions of the film feel repetitive; "Oh, no, someone died, let's split up and look for clues... Oh look, someone else died, let's split up again and look for clues again."
Beyond the film's strangely uneven tone and pace, the most distracting element for me was actually seeing a young Derek Fowlds playing one of the archaeologists. To me Fowlds is, and always will be, Bernard from TV's Yes Minister. How did this mild mannered public service secretary get caught up in this rambunctious affair? I know it's unfair to criticise a film for casting an actor because he will be typecast 10 years in the future, but I still found it distracting.
At the risk of sounding like a perennial fence sitter, Tower Of Evil was just another horror pic, in a long list of horror pics, that left me feeling ambivalent. It's not good, but it's not bad either. It just is. I'm sure Agatha would not be happy with such an ambiguous conclusion.