A mad baron keeps his son and daughter perpetually locked in separate rooms, not only to curb their unnatural desires for each other, but presumably in an effort to save them all from the "demons of the mind."

Does this all have something to do with the violent murders ravaging the countryside? You betcha.

Another atmospheric Hammer effort, with good performances by Briant and Hills.

It's all rather vaguely plotted, to be honest, but it's exceptionally dreamlike in spots, and the bloody ending is a nice capper.