Make your way to Mort'ton through the Mortmyre swamp. Go to the Haunted mine southwest of the village (go through Burgh de Rott or use the long, curling road with the snails). Use the main entrance to the mine on the top of the hill.

Follow the patch to the north, walking over the green stones.

Part I - Reaching the bank

It may seem like it's pointless to split this guide into two parts but it isn't. If you are unable to get to the bank before using more than 10 lobsters it is advised to use a teleport before the monsters kill you. This could be considered to be a test of how well you can survive.

1. Enter the dungeon. Walk north and you will notice you triggered a trap. You'll see small lines on the floor. Right-click and select search. You'll disable the trap.
   
   
   
   
2. Walk to the east while keeping attention to the floor. Half-way the second room is another trap.
   
   
   
   
3. The walls to the east aren't normal. Righ-click to disable the wall trap. You can also walk around these. But when you do, you risk the chance of getting lured in the trap.
   
   
   
   
4. Keep walking east as long as you can. Don't forget to disable those traps. The eastern path leads to the bank.
   
   
5. Part II - The dungeon
   
   Now restock your food. You need 100 GP to use this service. Enter the passageway in the "bank".
   
   
6. Go to the west side of the "n" shaped room. There are traps everywhere! Only the floor traps, so don't worry about evil walls. Take the southwestern most passageway.
   
   
7. In the room with the Giant skeleton are no traps. Use the north entrance.
   
   
8. The room you're in now has traps on mean locations. Walk to the middle of it first, then take the west entrance. Don't click directly on the passageway! You will walk on a trap if you do.
   
   
9. Turn north in this room. Both walls have spear traps. Pick one of both sides and disable that trap.
   
   
10. This is your only log trap. Use the pillars to jump to the far west side of the room, disable the trap, jump back and head north while the log is inactive. Right-click on the pillars to jump, but you probably figured that by now.
    
    
    
    
11. The small area has no traps. The corridor has two spear traps: one in the beginning and the other a few squares after.
    
    
12. Now you'll see the new bulldozers. Wait until they are done pushing air and walk between them and the middle. Repeat this at the second part of the ledge.
    
    
    
    
13. Enter the next room and the the map shows the route you should jump. When you have jumped half way put on Protect from Magic. Even with a decent combat level and decent armor you may need to flee fast. You do not want to have to teleport because you could not flee fast enough. Once there disable the floor trap near the stairs and climb down.
    
    
14. This room doesn't have any obstacles which are a danger for your health. Use the only exit, north. Get prepared by drinking your potions and healing yourself, you'll enter the boss' room.
    
    
15. Now you'll see a cutscene of the Grudge. Your prayer will get drained. This is just like the Barrows, but a lot faster. You can kill Tarn without killing the Terrordogs. He has two forms, both are level 69.
    
    
    
    He's very easy and won't respawn. You can go to the final study now, but if you are a high level, you might want to kill the monsters for some experience.
    
    
16. You only have the slayer experience left to get now! Take that book which is in the study and use it on your Salve amulet. It will now turn pink and give 20% to attack and strength while fighting the undead. This makes the dungeon an excellent training spot after killing Tarn.