"A Critical Mass" is the first section in The Celestine Prophecy.  The journey begins with James' meeting up with an old acquaintance for dinner.  Drawing him out of his "self-imposed isolation";  upon his arrival - Charlene is in a situation that could be seen as dangerous or mere happenstance.  This engagement inspires the author, James, to go on an expedition of a lifetime after learning the first insight of the ancient Peruvian Manuscript.