Reward: Lucien's Contract
No doubt you've been ambushed by Bandits before, but if you have engraved yourself into the habbit of walking around Albion you've most likely been ambushed countless of times. There are times that these ambushes will drop a piece of a map, once you collect four pieces you will unlock a new quest.
Go to the Forsaken Fortress in Brightwood, when you get there it will be overrun with Bandits, more than you're used to. You need to Kill the Bandit Darius Zing. Like the other Bandit leaders, Zing will run off after you've slain all of his followers. Run after him and fight off all of the Bandits that you run into. Eventually he will stop and join his henchmen and attack you. He isn't difficult to kill, it is easier to kill the Highwaymen first though.