Just about better than 'Return from Witch Mountain' , though 'Beyond Witch Mountain' is still a monotonous sequel.
Disney clearly gambled and put all their eggs in the television series basket, which never materialised. Therefore, as you can imagine, it leaves this underdeveloped. Some moments feel like a rehash on the original film, 'Escape to Witch Mountain' , while the rest is simply there to preview the would-be show.
It's better than the other sequel from 1978 (which is practically ignored) because it at least acknowledges the ending of the 1975 production. It unfortunately doesn't delve too deeply into it due to the earlier mentioned reason, but there's at least some progress with the story.
It's nice seeing Eddie Albert return as Jason O'Day, though Tia and Tony have been (understandably, given the seven-year gap) recast with Tracey Gold and Andy Freeman, the former is fairly solid in her role. A few other characters reappear, but all have different actors - they remain forgettable.
Normally a low (48min) run time would work in favour of a film that's disappointing, but it actually works against this one - made worse that there's no follow-up series as well. A missed opportunity.
