The BBC Four repeat of the 1977 story The Face of Evil, had mixed fortunes according to unofficial overnight viewing figures.
Part one on Monday had an average of 141,000 viewers, above the timeslot average of 79,000. Part Two, which followed directly had an average of 183,000 watching, below the timeslot average of 268,000.
However just 56,000 tuned in for Part Three on Tuesday evening, rising to 88,000 for the story's conclusion.
Final figures will be released next week, and will include those who recorded the programme and watched it later.
Parts one and Two had an Appreciation Index score of 84 with Parts Three and Four scoring 83.