 After defeating a rival railroad company and laying track to supply the US Cavalry near the Mexican border , Amelia meets a French prospector named Pierre Beaumont , who helps her and US Cavalry commander , Major Cooper , defeat a Mexican army attacking a fort . He then lures Amelia to a mine in Colorado where a surprise visit from an aged Kanyenke , who has brought Cooper and the cavalry with him , reveals Beaumont as the leader of Circle of Ossus . Amelia , Kanyenke , and Cooper chase Beaumont through the mines , where they find a map to the Lake of the Moon . 
