Getting the Items You Need
Before you start this quest it is a good idea to get all the items you require:
A Bronze Medium Helmet can be obtained through the Smithing Skill by smithing 1 bronze bar with a smithing level of 3. You can also buy these from Peska in the Barbarian Village for the price of 24 coins.
An Iron Chainmail can be made from 3 iron bars at level 26 smithing. You can also buy one from Wayne in Falador for the price of 210 coins.
For this quest freeplayers can pick a cabbage from these locations:
South of Falador:
North of Rimmington:
Northwest of Lumbridge:
The Monastery:
Or you can also farm your cabbage if you are a member and have level 7 Farming or pick them from many other locations. The important thing is that you do not pick cabbages from Draynor Manor:
Getting Started
Now that you have all the items you need, it's time to go and start the quest. To start the quest, talk to Sir Amik Varze on the 3rd floor of the White Knights' castle in Falador. If you have trouble finding him this is the White Knights' Fortress:
All you then need to do is climb up the western stairs to the third level of the castle:
Sir Amik Varze will send you to 'check on' the Black Knights' Fortress. So grab all your items and maybe some food and head to the Black Knights' Fortress:
Inside the Fortress
First of all wear your iron chain-mail and your bronze helm. Open the 'sturdy door' on the south side of the building. Now that you are inside, there is no further need to impersonate a guard so you may wear your normal armor. 'Push' the wall directly in front of you:
Climb up the ladder, then the ladder you find on the next floor. You should now be on the 3rd floor, however there re some boxes that block your way to the eastern half. There is a ladder heading down slightly to the east of you that you must then climb down. You will arrive in a room that looks like this:
Head up the ladder in the eastern room and you will find yourself on the 3rd floor again, behind the obstructive boxes from earlier. Head down the ladder that is just next to you.
This room is a safe haven. The black knights can not get to you, and you can recharge your prayer. If you are low on life you can wait here until some of it regenerates.
When you have recovered, exit the room by the door to the west. A Black Knight will be very hospitable and greet you with a fierce: "Die intruder!!!" And will attack you no matter what your level. You do not need to kill him, just run past and down the ladder. You will now be on the bottom floor again, run along the corridor and 'listen at grill'.
Your character will crouch down and over-hear the plan to give the Black Knights an invincibility potion... But do not fear, you can ruin everything! All you need is one small cabbage...
Destroying the Potion
Head back to the entrance of the fortress, just follow the guide so far in reverse order if you are worried about losing yourself. The door to the east is the door to the meeting room, try to go in but the guard will stop you:
Tell the guard that you'll go in anyway and run away from the Black Knights and up the ladder to the north.
Walk along this passage, and you will need to push yet another wall:
Inside here, use your cabbage with the hole in the floor.
Warning: Be very careful that you use the cabbage with the hole, because if you do not right-click you will eat it!
The witch will throw a fit.
Now you can leave to go get your reward from Sir Amik Varze. To get out you can back-track to the entrance and walk to Falador, or you can homeport and walk there from Lumbridge.
Rewards