When I set out to try and watch every pre-2000 horror film, I hadn't counted on there being quite so many bad films from Mexico during the 1950s and '60s. Invasion of the Vampires is a typically cheap Mexican vampire movie of that era, heavy on the dialogue and light on fright, with the only scene worthy of mention being an attack by a giant, furry vampire bat (the hilarious looking flying rubber rodent suspended on wires, swooping towards the film's hero, before being pinned to a wall with a wooden pole).
The unremarkable plot sees expert in the occult Dr. Ulises Albarrán (Rafael del Río) travelling to a small town that has been plagued by numerous mysterious deaths. At the hacienda of Count Frankenhausen (Carlos Agostí), he discovers that the count is a vampire, and sets about preparing a special acid (extracted from the roots of the mandragora) that can destroy the undead. However, when Albarrán successfully defeats Frankenhausen, the count's victims rise from their coffins as vampires (despite having already been staked!).
While the dreadful dubbing on the copy of the film I watched didn't help matters, I am certain that I would have found Invasion of the Vampires just as tedious in its original language with subtitles. There is way too much talk, the direction is pedestrian, and the plot is a jumbled mess of vampiric nonsense that generates zero suspense or scares. Apparently, this film is the follow-up to El vampiro sangriento, which I have seen, but subsequently forgotten; I imagine that Invasion of the Vampires won't linger in the memory for very long either.