Kim Richards, Ike Eisenmann, and Denver Pyle reprised their roles as Tia, Tony, and Uncle Bené from Escape to Witch Mountain (1975). This movie was also directed by the same director, John Hough, as well as having many of the same technical and production crew.
First of two collaborations of director John Hough and Bette Davis. They re-teamed for another Disney movie, The Watcher in the Woods (1980).
Bette Davis agreed to do this movie because it was a movie her grandchildren could watch. Also, Davis had three people tending to her on the set throughout the shooting of this movie.
Second of five "Witch Mountain" movies. This sequel was released three years after Escape to Witch Mountain (1975). Later came the second sequel, Beyond Witch Mountain (1982), then a television remake of the original, Escape to Witch Mountain (1995), then another remake, Race to Witch Mountain (2009).
This movie was unique in its casting of two suspense and horror movie genre legends, Bette Davis and Sir Christopher Lee, as cohort villains. This movie was the only theatrical movie where the pair were teamed together.