Apparently the bandit gang has taken hostages, so run into greatwood. Fight your way through to the fishing house and shoot the bad guy from afar with the arrow. Then fight off the guys that show up. You're thanked but apparently the sister is still a hostage.

Fight more bandits and move along. You reach greatwood lake. Yes, fight more bandits and then kill the final protector from afar. Yet more bandits arrive - slay them. She's happy.

She gives you treasure clue 1. 5630g plus a silver key is here at end of pier.

Fable Walkthrough