Reward: | 2500 coins and 3 Quest Points

First things first, you'll need to head to the White Knight's Castle in Falador. Find Sir Amik Varze upstairs and chat with him. He'll lay out exactly what you need to do for this quest.

Before you make your way to the Black Knight's Castle, which is located north of the Ice Mountain, you'll need to grab some specific gear. Make sure you have an iron chain mail and a medium bronze helmet. If you don't have them, you can craft them yourself. Once you're geared up, head over to the monastery that sits east of the Black Knight's Castle. In the field behind the monastery, pick yourself a cabbage. Now, with your gear and your cabbage, make your way to the Black Knight's Castle.

Once you're at the castle, put on your iron chain mail and your bronze medium helmet. You'll want to enter through the side door on the east side of the castle. Head north inside that small room and look for an odd-looking wall. Push on it, and you'll find a ladder – climb up it!

Up you go! Now, approach the grate and listen in. You'll overhear the witch discussing the secret weapon: an invincibility potion. She's expecting a little goblin to bring her a special cabbage, but he's apparently not going to cooperate!

Time to head back down. Descend the ladder and go through the door to the west, where the Black Knights are hanging out. A guard might try to stop you, warning you that those knights are dangerous, but don't worry – just head in anyway.

If any level 46 Black Knights decide to attack you, your best bet is to just run away. If you're feeling brave or need the experience, you can fight them. Either way, make your way into the south room. From there, go upstairs and then climb the ladder that's to your west.

You're upstairs now and have climbed the ladder. Head north and push against another odd-looking wall. This is where your cabbage comes in handy! Use the cabbage you picked earlier on the hole in the wall. Congratulations, you've just destroyed the witch's magical potion!

Now that the deed is done, head back to the White Knight's Castle in Falador. Find Sir Amik Varze again, and he'll be ready to give you your reward!