On the edge of an expedition takes the events of three random lives affected by the expedition of Christopher Columbus in contemporary-day America. Readers are given an account of a love interest as it reflects the dysfunctional dynamics of a cheating ex-lover. Then the story takes readers back to the time of Christopher Columbus and his relationship with his brother Bartholomew Columbus. As the story develops between Bartholomew and his account of the voyage, different strings of events reshape history. Lastly, the evolutionary production of O Gee and Larry who are characters from the past twentieth century are covering ground to give readers a hint of what the lime life entailed as a result of freedom from the eastern hemisphere.