Hmm, I tried several reviews but they say very little about the story itself. The closest one I found says:
"(the main hero) has to solve the mystery of the ancient Maya. He becames a part of a prophecy. Will he be able to retrieve the sacred golden key to allow the heavenly prophets to descend back to the Earth?"
Also, the story involves the nazis somehow. Although the game takes place in the presene time, I remember the intro was showing the nazi soldiers finding something in the South (or central?) America.
That's all I know, sorry. Hopefully someone will know more about it.