Oasis (quest)

Oasis is a Fallout 3 quest. It is also an Xbox 360 and PC achievement.

Objectives and walkthrough
Harold, a special FEV mutant with a tree on his head which he called Bob, eventually found himself overwhelmed by it and became rooted to the ground during his travels in the Capital Wasteland region. Here he was discovered by several people who began to worship him as a god, and a small and exclusive cult known as the Treeminders began to form in secrecy. Bob began to blossom and many plants grew in this area, which became green with life, a stark contrast to the outer wasteland.

Harold reveals his true identity, and begs for mercy; after being stuck in the same position for decades he is eager for death. The other dwellers of "Oasis" have ignored Harold's wishes so far, and ask you to instead either suppress or expand Harold/Bob's fertility.

Birch gives you some sap that will cease Harold's growth, and Laurel gives you her liniment that will increase Harold's growth. Entry to the cave system is gained from the main Oasis hub area, not the doorway within the same area as Harold.

Make sure to speak to Sapling Yew before entering the caves. If you succeed in the little speech challenge within the dialogue with her, this will unlock a reward after you return from the caves. An alternative is if you have The Child At Heart perk you will automatically succeed and will receive the award upon completion of the quest. This reward is given on either option for this quest, unless you fail in the speech challenge of course!

Once you enter the cave you have to navigate through. In the first section with the path alongside the shallow water there is one Mirelurk. Once you get to the room with the large irradiated pool of water, you will encounter 2 Mirelurks, and a Mirelurk King. You will have to swim underwater to find the passage to move onward, from the path entering this room just straight ahead. There will be 2 more Mirelurks and a Radroach. There's a door further down the cave. After you go through the door, there is a Mirelurks - Hunter. A pathway off to the left near the door has a small alcove where someone used to live. The skeleton is still there, surrounded by loot - including a Pre-War Book, D.C. Journal of Internal Medicine, and Silenced 10mm Pistol. Further along the path you'll pass another pool on your left side containing a Mirelurk. Diving in the pool reveals a couple of dead bodies with minor loot and a mini nuke. Just beyond this pool you'll hear a thumping sound. The thumping sound is Harold's heart. Walk upon it and you will be able to activate the heart, which gives you the 3 possibilities to proceed.


 * Destroy the heart or burn down Harold with your Flamer (*).
 * Apply Birch's Sap (stop the growth).
 * Apply Laurel's Liniment (increase the growth).

(*) Burning Harold will make the whole town hostile, and you will lose some Karma.

After you made/applied your choice, there are 2 ways out; one through a door in the room, which leads to a room with 2 more Mirelurk Kings and a Mirelurk that are very close together as well as another irradiated pool of water you will have to swim into to escape, or you can back track the way you came. Choosing the way through the door can be a good choice since it is a shorter way, there are some items (including a 9mm and a Sniper Rifle near the corpse on the right after entering/jumping down) in the cave and some ammo lying around + 1 ammo box. It can/will happen that the Mirelurk (Hunter?) will mysteriously show up behind you, if you choose to stay on the upper part of the cave and kill from up there.

After the fight you just dive again, and will end up, after passing the last door, in the area with Harold in it. Depending on your choice, there will be Birch or Laurel waiting next to Harold, thanking you for your help on either option you chose. The name the persons who will give you you rewards.

Rewards
for helping Harold grow


 * Bloomseer Poplar offers you the Poplar's Hood
 * Branchtender Linden offers you the Linden's Outcast Power Armor

for stopping Harold's growth


 * Branchtender Cypress offers you a Missile Launcher + 1 or 2 Missiles
 * Branchtender Maple offers you the Maple's Garb

for killing Harold


 * As a reward for this option you receive (immediately after destroying the heart) the Barkskin perk wich gives you 5% additional damage resistance.

Harold also has some more dialogue about your choice, if you choose to speak to him.

If you succeeded in the little speech challenge with Sapling Yew, you will receive the Yew's Bear Charm from her on either option you made.

Bugs

 * Telling Fawkes to wait in the cave while the PC completes the quest may cause the game to crash or freeze when the player attempts to reenter the cave.
 * Sometimes Sapling Yew will not offer you the charm. This may be due to a glitch or simply not performing or successfully using the Speech challenge or Child at Heart dialogue.