Guild Wars 2 – Assault on Moledavia

Head over to the marker to get into the instance in the Diessa Plateau. It is only a quick run inside it to start the instance properly by interacting with the warband's leader, Ballista.
Ballista: “Moledavia's a tough nut to crack, Slayer. Strong walls, turrets with a clear file of fire … we can hit them with mortars, but that's only the first step.”
Slayer: “All right, I'll take mortar durty and deal with the turrets and the walls. Then we should be clear for a frontal assault.”
Ballista: “You got guts. Too bad I can't keep you for long. Mangonel! Show the slayer to the mortar battery.”
Mangonel: “Right away, Legionnaire.”

Follow Mangonel as he leads you from the starting position a ways over to the mortars. Mortars are not the hardest thing to control. The thing you need to keep in mind, especially if you have a lot of enemies to deal with is the cooldown time. Still, it is not the most important part of what is going on here. Start by blasting whatever turrets and walls are in your direct line of fire. Use the lengthy range of this weapon as much as possible. After a while of blasting you will make it through the outer walls and will have access to Moledavia. When Mangonel tells you it is time to head in, exit the mortar and head on in to Moledavia.

You are treated to a quick overview of Moledavia as you enter, pointing out the location of the chugger. Head inside and start slaughtering as many dredge as you care to. You have a short ways to go to get through the whole of the instance. Just keep up a good pace and watch your health. It does not mean restarting but running the whole distance can get annoying. The main things to be wary of are any remaining turrets and the Storm generator.

When you make it to the chugger you will have one final bit of fighting to do. It consist of multiple waves of Dredge and in massive variety too. Plow through the few waves of the dredge and then you will finally be able to claim the chugger from within the depths of the earth. This leads to one more cinematic for this mission:
Ballista: “Not bad, for a huge Norn lush. Now that you've helped us recover the chugger, it's only fitting you see it in action. What do you say soldier?”
Slayer: “I'm in … boss. See? I'm finally getting the hang of all this soldier talk. What's the plan?”
Ballista: “Ascalonian ghost have been attacking our supply caravans near Grendich Ruins. We're order to secure the area and wipe them out.”
Slayer: “Good. It's an honor and a joy serving with the Gear Warband. Besides, I never got a chance to fight that big gun.”
Ballista: “Outstanding. Meet us at the ruins and you can light up all the hostiles that you want.”

With that, choose your reward and head on out of the instance. It is time to move onto the final mission in the storyline, “The Machine in Action”.