Storming the Fortress

Entering The Fortress
Talk to Jimmy and tell him about the "big gate". He'll give you a rope so use it on the collapsed wall. Hide behind the walls so the level 90 Dark knights can't see you. Go south until you reach a fountain, then go west. Run all the way to the end until you come up to another fountain, then go north. After you reach a path, follow the path to a ladder and a guard will be guarding it. Kill him and go up the ladder. Go south to a small shed and take the hammer inside. Go back to the ladder and use the hammer on the nearest window. You'll then break the window so click the broken window to enter the fortress.

The Fortress Interior
Go down the spiral staircase to enter a room full of guards. Run past the guards (or kill em if u want) to the door and go through it. There will be three rooms, go to the last one on the right and climb up the stairs. You will enter a room full of crates and a guard dog. After you kill the dog it drops a key which you need later on. Go through the door east of the room, you'll be in a hallway full of guards. Go the end of the hallway and climb up another flight of stairs. You'll be at the west wing now.

Taking Out The Cannon
Go to the construction area. Kill the guard that is guarding the door, hell drop a key and use the key on the door. Go through the door and you'll see an unfinished bridge and a door leading to a storeroom. Use the key you got from the dog on the door to find a tinderbox, another rope and a saw. Go out and walk over the unfinished bridge. In the middle you'll see a huge gap, jump over it (requires 80 Agility). There will be 5 guards and a dark knight. Kill the dark knight first and he'll drop a manual of some sort. Keep going straight and you'll see a huge cannon. Enter the shed south of the cannon to find explosive shells. Take one and use the saw on it. You'll get some gunpowder. Go to the cannon and read the manual on how to operate it. Once you've finished, use the cannon controls and target the big structure near the construction site. Click the red button to fire it and the entrance to the structure will explode. Next, target the big dark knight symbol on the wall of the fortress.34. Fire the cannon and the building will explode. Use the gunpowder on the controls then use the rope and finally the tinderbox to blow it up. You'll then see a cutscene where the cannon falls apart and the building is about to explode.

Escaping The Fortress
Go to the structure and take 5 planks and 25 nails. Go back to the unfinished bridge which now you see a big part of a wall slamming into the bridge. Use your hammer on the bridge to fix it. After you've fixed it a time bar will show up on the top of the screen. You need to get out the way you came from. When you reach the broken window the ladder has fallen and you can't get down. Go back down the spiral stair case and into the big hallway (not the one before). Try opening the large front door of the fortress and you'll fall down a trapdoor.

The Final Battle
You'll appear in one of the Slayer Cave tunnel complex. Keep going where the tunnel leads you. You'll enter a massive room. One you've entered the tunnel collapses behind you and 5 dark knight titans enter the room. It is a multiway combat area so to ensure that not all of them fight you at once, wait for all 5 of them to appear, then walk to the collapsed tunnel and they'll line up in a straight line so you can fight them one by one. After you kill them, Jimmy finds you and lowers a rope so you can climb it. After you climb up, talk to Jimmy.

'''Congratulations! Quest Complete.'''

Rewards

 * 4 quest points
 * Access to the fortress
 * Access to the fortress
 * Access to the fortress