[TOMT] [TVShow] An episode from an unknown show

Hi everyone!

I'm trying to identify what I believe was an episode from a live-action horror anthology series, similar in style to Are You Afraid of the Dark? or Goosebumps.

Here's what I remember:

A group of teenagers are exploring a forest when they come across a cave. Inside the cave they discover an ancient altar with a cup or chalice filled with a red liquid that looked like blood.

There is some kind of warning on the altar stating that the contents of the cup must never be spilled, otherwise darkness will fall upon the Earth.

While messing around, the teenagers accidentally spill the liquid. When they leave the cave, they discover that the warning has apparently come true. Although it is the middle of the day, the entire world is covered in darkness as if it were nighttime.

Terrified and believing they caused it, they try to find a way to reverse the curse. Eventually they conclude that the cup must be refilled with blood and returned to the altar. The problem is that it requires a large amount of blood, so after a heated argument they decide to sacrifice one member of the group.

They kill their friend, fill the cup, place it back on the altar, and leave the cave. The daylight returns and everything seems normal again.

However, shortly afterward they hear a news report on the radio stating that the darkness had actually been caused by a natural phenomenon and that it had passed on its own. The surviving teenagers are left in shock. Rather than accepting that they murdered their friend for nothing, they convince themselves that the news report must be wrong and that they were the ones who restored the light.

That's the ending as I remember it.

I watched this many years ago and have never been able to find any information about it. Does this sound familiar to anyone? Any help would be greatly appreciated.