First off, speak to the Warrior in the campsite located southeast or Draynor Village and he will start telling you about what they are searching for. Ask him "Who is Zanaris?" and he will tell you that Zanaris is not a person; it's a hidden city of treasure! Ask him "How are you finding it if it's hidden?" and he mentions a Leprechaun hiding somewhere in the trees.

 

The Leprechaun should be hiding in a tree directly west of a nearby Pot respawn. You'll be able to tell which tree it is, as when you hover over it there will be a "Chop Tree" option (as opposed to the usual "Chop-down Tree" option).

 

When you try to cut his tree, Shamus the Leprechaun will jump out and you'll have to catch him. When you talk to him, he will tell you about the Dramen Staff needed to enter Zanaris.

 

Entrana is an island that can only be reached by boat. The island is watched over by peace-loving Monks, so you'll be unable to bring any weapons of armor to help you. However, you can bring Robes, Amulets and Runes (anything not weaponry).

Note: There have been reports of a monk "appearing" out of nowhere and taking your newly-created weapons and armor, and knocking you out cold and sending you back to Port Sarim, so it might be best to bring extra supplies.

 

If you're planning to Range the Tree Spirit using a Bow and Arrows, bring an Unstrung Bow, a Bowstring, Arrow Shafts, Feathers and Arrow Tips, along with Food, a Knife and Teleport Runes. Remember, you'll be Fletching your own Bow and Arrows when you reach the island, so bring enough supplies! You can also craft some leather on the island, so bring some Leather, a Needle, Thread (studds if you wish to make Studded Armor). If you're not going to Range it or if you don't want any Leather Armor, just bring a Knife, food and Runes.

 

Head to Port Sarim when you're ready and speak to 1 of the Monks of Entrana found on the northern pier. Ask to go to Entrana, and he will search you for any weapons and armor. After you're cleared, you'll soon be on Entrana!

 

Once you're there, Fletch a Bow and some Arrows. Go to the northern part of the island and you'll see the dungeon. Climb down once you are ready, and the Cave Monk will warn you about the danger of the cave (Note: Once you're inside, there's no quick way out, so be sure you're ready!).

 

The Tree Spirit

Once you're inside of the dungeon, you'll find some level 25 Zombies; kill them until you find a Hatchet. Run past the Greater Demons until you reach the Dramen Tree.

Put Protect From Melee on (if you can), attempt to cut the tree down and you'll be attacked by a level 101 Tree Spirit! It's a difficult fight with just a Hatchet, but it's possible with Prayer. It's easier if you brought a Bow and Arrows or some attack Runes, as you can hide behind the Mushrooms to attack it.

 

Once the Tree Spirit is dead, chop the Spirit Tree to get a Dramen Branch or 2. Now just teleport out, or run past the Greater Demons through the Portal and into the High-Level Wilderness. Now just cut the Branches with a Knife to get a Dramen Staff.

 

Go to the little shack in the Lumbridge Swamp, southeast of the Adventurers, wield the Dramen Staff and go inside. You'll be teleported to the Lost City of Zanaris, and you can now explore the entire city! Congratulations, quest complete!

 

Rewards
The ability to cut Dramen Branches and make Dramen Staffs.
The ability to enter Zanaris by wielding the Dramen Staff and entering the Shed.
You can now wield Dragon Swords and Daggers, and you can buy them from the market in Zanaris by giving a Cut Diamond to the Guard.
3 Quest Points