Through The Cave by Wilbert Gillham

Strange and unexplainable things begin to occur when Tex, a down-on-his luck ex-con, tries to kidnap Kalynda, a college student from a wealthy family, and Kyle, a high school student, falls into a secret cave while outrunning the school bullies. Where will that cave lead? And who really is the mysterious woman that keeps appearing and seems to know everything about Tex?