We're back in the world of Hammer production values (now subtly calling themselves Tyburn), where no moorland scene is complete without a smoke-bomb billowing away just out of camera range, and well up to the usual mediocre level of British horror. Violin-playing ex-missionary Cushing arrives back from India with A Horrible Secret and a mystical servant (Watford). Bright young things crash their motor outside the front gate, and are whished away in by poor mad Tom (Hurt, sadly wasted). You should be able to fill in the other details. The familiar brisk script ('These marshes were used by the army as a training area, but they lost too many men') is by John Elder.