Some of that, of course, is just a marketing ploy: naming a film The Brides of Dracula (with the poster advertising 'the most evil, blood-lusting Dracula of all!', no less) when the prologue immediately explains that Dracula is (still) dead is at least a tiny bit cynical. Sexing up the property by using a premise designed to have lithe young women wander around in nightgowns is as shameless, but it's not like vampire fiction was ever particularly wholesome.
A young schoolteacher, Marianne Danielle (Yvonne Monlaur), is on her way to a new job at a girls' boarding school in Transylvania when, through shenanigans inexplicable and foreboding, her coach driver abandons her. She accepts the offer of a seemingly lonely aristocrat, Baroness Meinster (Martita Hunt), to spend the night at her château. (Note to self: refuse any invitation that begins with, "My castle is in the hills above the village...")
At Château Meinster, Marianne discovers that the baroness is not quite alone: she keeps her son (David Peel) chained up in one part of the castle, ostensibly because he is mad. During the night, though, Marianne frees the baron after he tells her his mother has locked him away to keep his land and titles for herself. To nobody's surprise, this is a terrible idea. Although Marianne does not understand it yet, the younger Meinster is in fact a vampire, kept confined for years and fed a steady diet of young women by his mother, who could bear neither to let him loose nor to dispatch him. Now that he is loose, he quickly takes off with the aid of his nanny, Greta (Freda Jackson).
The following day, Doctor Van Helsing (Peter Cushing) finds a traumatised but otherwise unhurt Marianne in the woods. He asks her detailed questions about her experience, but fails to tell her what's going on. After dropping Marianne off at the girls' school, Van Helsing investigates the Château Meinster. There he encounters the baroness, who has been turned into a vampire by her son against her will. Van Helsing stakes her in her sleep, but finds the young baron's coffin missing. That the threat isn't over becomes obvious when a young girl in the village nearby dies from a neck bite. And soon, Marianne is engaged to be married...
The plot of The Brides of Dracula starts strong, but descends into a frustrating muddle by the second act before hurtling towards an outright nonsensical conclusion. If Van Helsing had told anybody except the village priest (Fred Johnson) about the vampiric goings-on lives might have been saved, but I'd forgive that contrivance if The Brides of Dracula didn't also feel like two separate stories stitched together: one about a lonely mother who keeps her vampire son locked up, the second about a hypnotic vampire who draws young women into his coven. Most frustrating are the half-developed characters. Freda Jackson (from Nottingham! fist bump) turns in an outstanding performance as Greta, whose sour-faced demeanour hides a fanatical devotion to Baron Meinster. She's rewarded with a terrific soliloquy early on; thereafter, the script decides she'll be a cackling goon, and she is eventually killed off in a decidedly underwhelming fashion.
Jackson is splendid, but she's far from a lone standout. Hunt's Baroness Meinster is as impressive, all austere aristocratic dignity covering desperate love for and fear of her monstrous son. Cushing turns in another excellent performance, settling into the role and beginning to hone his characterisation of Abraham Van Helsing, battling the forces of evil with science! Yvonne Monlaur, drop-dead gorgeous in a very sixties way and working an adorable French accent, hits all the right notes; it may not be a performance for the ages, but it's enough to regret Monlaur retired from acting only a few years later. The problem, really, is the villain: Peel is good as a brash young baron but never develops a take on monstrous bloodsucking, and he absolutely lacks the astonishing physical presence of Christopher Lee. Where Dracula was a terrifying battle against evil, its sequel just has me rooting for Cushing to beat up a blue-blooded punk.
Despite being a bigger, sexier and more action-packed sequel The Brides of Dracula also makes some significant adjustments to the series mythology: shapeshifting, explicitly ruled out in the 1958 film, enters the series here, with a not-terrible giant bat effect. Vampires now need human servants to watch over them during the day (they learnt from what befell Dracula's original bride, I presume). Elsewhere, what was hinted at in Dracula is more fully developed, first and foremost the notion of vampirism as 'the cult of the undead', 'a survival of one of the ancient pagan religions and their struggle against Christianity'.
Certainly, Baron Meinster's coven has the character of an extremely patriarchal religious community, and in portraying it as supernaturally wicked The Brides of Dracula inadvertently ends up critiquing patriarchy even while exploiting it to pander to the audience. It's a good film, is what I'm saying in a roundabout way: it doesn't blow the roof off the horror film, but it's a very fine example of the developing Hammer template.