Items Needed: Weapons, Food, Armor
Skills Needed: Level 25 Agility, enough combat to kill a lvl 172 Black Demon
Rewards: Attack experience (about 18k for me), Agility experience (about 7900 for me), 5 Quest Points, access to Gnome gliders, more Spirit Trees, the mine under the Grand Tree.
You can start this quest by completing its prerequisite quest, Tree Gnome Village, and then talking to King Narnode Shareem in the Gnome Stronghold.
The King leads you downstairs into the foundation of the stronghold to speak with you. He explains that the Grand Tree that forms the stronghold is ill and is deteriorating rapidly. He asks you to investigate the cause. He hands you a bark sample and a translation book, and sends you off to find Hazelmere, on an island east of Yanille.
Make your way to Yanille, and head east across the bridges. Enter the small hut and go up the ladder to speak with Hazelmere. Although he says nothing but 'blah', he gives you a scroll after you give him the bark sample. The scroll reads:
Using your translation book, it comes out to:
A man came to me with the King seal. I gave the man Daconia rocks and Daconia rocks will kill the tree.
Head back to the tree gnome stronghold. Talk to the King, and go through 'None of the Above' until you see a phrase matching the messages. The other choices are all quite amusing, but won't get you anywhere. The King says that someone must have forged his seal. He asks you to warn the tree guardians.
One is named Glough, and he's just east of the ramp leading up to the Grand Tree. Glough will brush you off and tell you to go back to the king. The king will then tell you that Glough captured a human with 3 Daconia rocks. Head to the top floor to talk to Charlie.
Charlie reveals that Glough was paying him to deliver Daconia rocks. Investigate Glough's home. Search the cupboard and take Glough's journal. Read it. Confront Glough, and you'll be arrested and thrown in with Charlie.
He'll tell you to talk to the foreman at the Karamja Shipyard with the passcode Ka-Lu-Min. The king will spring you from prison shortly afterward, and tell you to use the glider to bail.
You'll crash land somewhere on Karamja surrounded by Jogres. Head east and enter the shipyard by telling the worker that you were sent by Glough. You'll find the foreman on the end of the southern dock. He'll lead you to his office, where he'll question you. Answer any of the three (there's one specific sequence that gets you out of the fight, but I didn't bother) and he'll attack, although you can kill him handily. He drops a lumber order. Exit the shipyard and cross the river on the rotted log. Head back to civilization by going northwest and sailing to Ardougne. Go to the stronghold (two methods: speak to the hauler outside the stronghold, or use a spirit tree), and talk to the King.
Although the King doesn't believe you, if you speak with Charlie upstairs, he'll reveal that Glough left the keys to his chest at his girlfriend's house, Anita, who lives west of the toad swamp, which is northwest of the Grand Tree.
Talk to her, and she'll hand you the chest key. Popping open the chest reveals Glough's invasion plans.
Talk to the King now. He'll give you a bunch of twigs, shaped into a T, U, Z, and O. The translator will reveal this word as meaning 'Open'. Enter Glough's house, and climb the nearby tree. Use the twigs on each pillar to form the word. Pop open the trapdoor underneath, and go down.
Kill the black demon that Glough spawns. Go through the underground pathways to find King Narnode. Talk to him, wait through the long conversation, and he'll ask you to help find the rest of the Daconia rocks. Search roots throughout the tree until you find the Daconia rocks. Speak with the King to finish the quest.
Rewards: 5 Quest Points, 7,900 Agility Experience, 18,400 Attack Experience, and 2,150 Magic Experience
Note: As well as the rewards above, the gliders and spirit trees can now take you to more places. The gliders will take you to Shilo Village, the Gnome Stronghold, White Wolf Mountain, Al Kharid, and Varrock. You can now use the spirit tree in the Gnome Stronghold.