1. You can start this by talking to Squire who is located in the White Knight’s Fortress in Falador. He will ask you go to talk to Reldo who is located in Varrock Castle Library. Make sure you do not ask him for a quest since you already started The Knight’s Sword quest when you first talked to to the Squire.
2. After talking to Reldo, you will talk to Thurgo. Make sure you have you’re redberry pie with you when going over there. You can find him in Port Sarim.
3. Give him the redberry pie and it will get him in a better mood than he currently is at the moment. After finding out what he needs, a picture, then head over to the White Knight’s Fortress and talk to the Squire to find more information about the picture. While you’re still in the White Knight’s Fortress head over to you’re east and upstairs.
4. You should find you’re way up there with the images above. Once you get to the cup board, search it and you will find a picture. Take this picture along with you’re two iron bars, blurite ore and picture to Thurgo. If you do not have a blurite ore, then when you get to Thurgo you can go down the cave which is next to Thurgo’s area and you can find some blurite rocks in there so mine them and you will get some blurite ores. Make sure you are at least a level 10 mining and have a pickaxe along with you.