Here in Chapter 3.1 on Hunted: The Demon’s Forge you start out where you left off in Chapter 2.6, on the bridge.
Make your way across the bridge. Along the way, you’ll find a chest of gold. Collect it. Then, free the prisoners. When you go deeper in the forest, you’ll come across some ruins. To your right, there will be tall grass. Cut through this grass, and collect the gold along the way. There will be a guard you should talk to. Continue through the tall grass, and stop to collect the nineteenth Death Stone from the corpse that you come across. There is a bridge close by with an explosive on it. What you want to do is shoot at the explosive to detonate it. Then continue along the way through the door. There will be debris in your way. Just bombard it using the catapult.
From here, you have completed Chapter 3.1 of Hunted: The Demon’s Forge.