Sauron is dead(?) the elves have left, the land is war torn and there remain many thousands of dark servants scattered and broken. In the midst of all this, New rulers try to bring order to Middle Earth.
Minas Tirith is a scarred city. It needs aid to rebuild from the War with the Dark Lord Sauron. The call goes out for aid, but there are few if any in a better place to help. Gondor has lost a generation of sons, and has nothing to trade or offer. In desperation the new king turns his eyes south and east, keen to forge alliances with recent enemies now the influence of the evil one has been lifted. Easterlings, Haradrim, and Umbars are all sought for trade and friendship. Minas Tirith looks to the river ways to bring trade and prosperity, perhaps even to rebuild the lost Osgiliath in time. So it is you find the river ways full of traders and entrepreneurs, adventure seekers and opportunists, all keen to make a life amongst the post war rubble. Perhasp there are even those prepared to take a life to further their aims. It seems that even though the foul one is no more, and the Forth Age is the coming of Man, but evil still lurks in Middle Earth.