Concord Coaches hold a mythical place in the history of the Old West. Colfax Shaw and Anna Taber, born a hundred years apart, find a compatible interest in one old Concord. Anna studies the math of situations and timelines while Colfax focuses on the history of it all. But both the math and the history, normally solid and dependable for both Anna and Colfax, suddenly become erratic. All because of a Concord stagecoach. Another exciting novel in the Thunder Mountain series.