Connor must find and kill William Johnson.
Optional Objectives
Reach Johnson undetected
Kill Johnson before a Native American is killed
Swan dive from atop the cliff
Objectives
Reach the meeting hall atop the cliff
Walkthrough
Go and talk with Achilles on the ledge to conclude the last mission properly. There is a skip forward and it is reported that Johnson got the money he needed to buy the land. It is time for Connor to bring this whole thing to an end permanently.
You need to climb up to Johnson Hall and confront Johnson about the purchase of that land.