Ok, so the general idea is this:

The Lurish Empire recently experienced a surge in economy and technology, so the Emperor has demanded land, and has taken much of the globe by military conquest or purchases. However, much of this land is uncharted on modern maps, and is most often thick, nigh impassible jungle. So the Empire is now in need of intrepid explorers to go out and explore much of the new holdings of the Lurish. In the jungle, there live many native tribes, who react in various ways to the explorers and the civilization they represent. You can play as either an explorer, working on behalf of the crown to chart out the land, or a native, trying to form an alliance/resist the influence of the Empire.

The Lurish Empire may or may not be loosely based on the British Empire, so the time period equivalent is 1700-1800