The Spirit Mountain Mystery by C. C. Brower

The Legend of the haunted Spirit Mountain isn't that old. Just a few decades.

And something to do with secret government experiments in hidden bases deep in the desert.

They must have thought no one would ever find out...

When strange weather patterns started affecting local crops in near-mystical ways, the Ghost Hunters got their assignment: find out if it was some sort of trapped spirit who was causing this disruption. Move them on if they could.

But the underlying conflict they found endangers lives of not just humans, but immortal spirit guides as well. 

And any continued existance on this plane was caught in the middle...

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