I've been trying to find this for years but I can't remember much about it, anyway, here it goes. This was *maybe* a BBC production or the like and what I remember was two kids, maybe brother and sister, and they were both given some kind of magical stone that they're not suppose to drop. But at some point the boy messes up and drops it or looses faith or something. I also remember them running from some evil thing in some kind of tunnel and this was like the trailer for the next episode. At the end they both have to hold their stones and make some kind of magical arch but they boys stone almost doesn't work cause he dropped it at some point. Ok, that's all I remember, hope someone remembers this too... it was on cable TV (maybe PBS but not sure) in Madison, WI sometime in the 80s, maybe around 85ish. Thanks for the help!

Maybe a Nickelodeon series
Shown within
The Third Eye

Mini-series title:
Under the Mountain

Wow! You could be right, I really enjoyed a bunch of different Nickelodeon shows at the time, and the New Zeland production is maybe why I thought BBC... I'm going to find this and check it out. Completely Amazing!!

I just saw the episode "Red Force, Blue Force" and the scene where they old man reviles the two stones. I really can't believe I'm seeing this, thank you so much for helping!