This was expected to be the final film in the series, and it is by far the worst. Amy Ball would only agree to shoot for one day but they needed her for billing purposes so she appears in six minutes and twenty-eight seconds of the movie. Jesse Merlin's performance is edited together entirely from archival footage and outtakes from the previous movies while he was engaged in yet another bitter legal battle with the producers for walking out on the last "Morlock."
The rest of the film is Glenn Simon (who plays Amanda Globe's fiance) coming to Olga's gypsy seance parlor to try and find out what happened to Amanda when she strangely disappears. The story is told in flashback that she has been killed by Morlock's henchman Ruprecht (played, as always, by Tom Ackerman in exchange for a boxed lunch and deferred pay) and taken into hell by Morlock.
The film did not make its meager budget back at the box office although it became a staple on late-night television over the years. With its poor showing on initial release, the Morlock franchise was thought to be dead. But like the professor himself, it would come back to live again and again and again...