Explains the Monserrats to a complete stranger (Ian Ogilvy, TV's Return of the Saint) they've secured in what looks like an electric chair, the couple has devised a scientific system offering "complete abandonment with no thought of remorse intoxication with no hangover, ecstasy with no consequence." (To the viewer, this means a sequence of kaleidoscopic psychedelic sensurround freakout.)
In short, that enables Dr. and Mrs. Monserrat to link to him psychically, to see what he sees, to feel what he feels, to experience what he does. Lucky for the aging Karloff, who died within two years, this plot allows him to deliver much of his performance sitting down. Given the horror icon's involvement, the most interesting thing about The Sorcerers is how he turns out not to be the villain; the film leaves that to Lacey, who relishes responding as vile as director Michael Reeves allowed.
Better known for directing Vincent Price in 1968's Witchfinder General (and then for fatally overdosing the following year), Reeves does not have a similar grasp on the material here. Once we get over the novelty of the Monserrats getting over the novelty over experiencing such singular sensations, the heady brew of The Sorcerers no longer intoxicates. It looks great all the same thanks, Elizabeth Ercy! but merely simmers from there to a bitter end. Rod Lott