A terrible curse afflicts the house of Zorn. Baron Friedrich (Robert Hardy) is torn between a supernatural explanation for the madness plaguing his children, Elisabeth (Gillian Hills) and Emil (Shane Briant). Meanwhile, several local girls are being murdered, their bodies sunk in the lake by the family’s faithful servant, Klaus (Warren). Elisabeth escapes her father and creepy Aunt Hilda (Yvonne Mitchell) to tryst with idealistic student Carl Richter (Paul Jones), who takes an interest in curing her strange malady. But the villagers are stirred into action by a ranting priest (Michael Hordern) and Baron Friedrich’s faith in demented mesmerist, Falkenberg (Patrick Magee) yields disaster.
Written by Christopher Wicking (Scream and Scream Again (1969)), Demons of the Mind tweaks Hammer’s epic metaphysical conflict between good and evil into unsettling, psychological dimensions. Instead of the usual monsters we have two, frail flower children slowly being driven mad by sexual repression, psychological torture and suffocating parents. There are no wise, rational Peter Cushing-style father figures. Science is represented by a scheming charlatan, while religion takes the form of a babbling, possibly insane priest, each brilliantly played by Magee and Hordern. If there is a flaw, it’s that while Wicking and Peter Sykes deconstruct conventional horror film morality, they fail to provide any substitute. Jones’ cloddish, ineffectual hero is part of a long line of dullards in seventies Hammer fare, the exceptions being David Warbeck in Twins of Evil (1971) and Horst Janssen in Captain Kronos: Vampire Hunter (1972). A similar hindrance is the plummy overplaying of Robert Hardy, in a role Hammer offered to Paul Scofield and James Mason as a means of highlighting what an unconventional and prestigious project this was meant to be.
It didn’t work. The film was practically thrown away by its distributors and Wicking and Sykes did not return until their similarly ambitious and afflicted To the Devil a Daughter (1976) drove the final nail in Hammer’s coffin. While the film walks a daring tightrope between art house and exploitation, some critics firmly entrenched in either camp believe it works as neither. Certainly, its determination to deliver the exploitation goods - opening as it does with Elisabeth’s nude liaison with Carl - makes for a disorienting story-structure, but Arthur Grant’s colour drained cinematography and a creepy psychotherapy scene involving bar girl Inge (Virginia Wetherell) show some care taken to craft a deeper tale. Shane Briant’s pallid, pretty-boy frailty and Gillian Hills’ wide-eyed, willowy beauty make them two of Hammer’s most affecting “monsters”. The much-loved (by me, anyway) starlet from cult children’s show The Owl Service (1969) showed a propensity for threesomes in Blow Up (1966) and A Clockwork Orange (1971), but fans should seek her in the ultra-rare giallo: Hot Lips of the Killer (1974).