Oasis (quest)

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

Objectives and walkthrough
Harold is a special FEV mutant who appears in Fallout, Fallout 2, Fallout 3, and Fallout Tactics. Harold has a tree, which he called Bob (or Herbert as an inside-joke), growing from his head. Bob eventually overwhelmed him, and he 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.

The ritual
When the player approaches Oasis, Tree Father Birch will ask that the player follow him, saying that "He" has summoned him/her. If agreed to, Birch will unlock the gate to the village and lead the player to an outdoor hut. Birch explains that he is the leader of the Treeminders, and that "He" has summoned the player to the village. Although vague about who or what "He" is and wishing the player character to find out on their own, a Speech Check may be passed to discover what "He" is. The Treeminders ask that the player drink a sap in a ritual to purge the PC of all evil that might be inside him, so that "He" may go unharmed.

After the ritual, the PC is placed in The Grove, where they meet Harold. 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 instead to either suppress or expand Harold/Bob's fertility.

To your left after leaving The Grove, an argument between Tree Father Birch and Leaf Mother Laurel is witnessed. Birch wishes to stop Harold's growth with a sap (the same one used in the ritual) in order to protect him, and Laurel wishes to apply a liniment that will accelerate it, to spread his influence to the entire wasteland. Both want the player to side with them, leaving the others' wishes ignored.

This leaves three basic choices to go about this quest:
 * Side with Birch and apply Birch's Sap to Harold's heart to stop his growth.
 * Side with Laurel and apply Laurel's Liniment to Harold's heart to accelerate his growth.
 * Side with Harold and destroy his heart, killing him in the process

Instead of these options, Harold may be burned down with a fire-based weapon such as the Shishkebab or Flamer (plasma and mini-nukes seem to work, along with nuka-grenades). If this is done, the player will receive negative Karma, and all of Oasis will become hostile.
 * NOTE: Neither the A3-21's Plasma Rifle nor the Burnmaster will work for this; you have to use the non-unique variants of these weapons.

After the argument
The rest of the Treeminders are willing to talk at this point, who will express their views on the situation. Your reward is based on what you decide to do to Harold's heart and who you speak with before entering the caves.

Regardless of what you choose to do to Harold's heart, speaking with Sapling Yew beforehand is recommended. If you ask her about her "god", a speech check will become available allowing you to discover Harold's fear. If you pass the speech check (discovering that Harold is afraid of fire) but choose not to burn him down to complete the quest, she will give Yew's Bear Charm after completion of the quest. The Child at Heart perk can be employed as an alternative to guarantee success.

The other Treeminders may also be spoken to, and can give gifts after the quest. Note that it has been reported by a PS3 user that if not spoken to, they may not give the rewards after the quest, whereas a 360 user has claimed that it is not necessary. As long as all the Treeminders are not angered through dialogue, any path through it should work.

If you plan to side with Birch...
 * Speak with Branchtender Maple before entering the caves and ask her about how she ended up in Oasis. She tells the player about how she felt that she was chosen to come here, and fears that outsiders will eventually find and ruin the Oasis.
 * Speak with Branchtender Cypress before entering the caves and ask him how he became a Treeminder. He states how Birch took him in, and told him how important it is to keep Oasis a secret from the outside.

If you plan to side with Laurel...
 * Speak with Bloomseer Poplar before entering the caves and ask her about "her god." She will state her views about how Harold is not only her god, but everyone's god, and should be shared with the entire wasteland.
 * Speak with Branchtender Linden before entering the caves and ask him how he ended up in Oasis. A speech check can be passed to get him to explain how he was once a Brotherhood Outcast, and was found injured by the Treeminders. After being nursed back to health by Bloomseer Poplar herself, he decided to join them.

If you plan to side with Harold... If you plan to use fire...
 * There is no need to speak with anyone prior to entering the caves, with the exception of Sapling Yew.
 * As is stated above, Harold is afraid of fire, and can simply be killed with any flame weapon. The Flamer, Heavy Incinerator, Plasma Rifle, Missile Launcher, Nuka Grenade (it doesn't even have to detonate. As long as it hits him, he will be set ablaze.), Plasma Grenade, Mini-Nuke or Shishkebab will work on him. A simple hit scored will set him ablaze. Once on fire he will roar loudly and shake violently until dead, this will cause all of Oasis to immediately become hostile to you.
 * Note: Despite the name, the Firelance does not work. Setting off a plasma mine doesn't work, either, nor does a frag mine set him on fire. Although a unique flamer, the Burnmaster doesn't burn him, since it isn't affected by the pyromaniac perk, therefore isn't considered a fire weapon.

Into the caves
The main entryway to the cave system is in the main Oasis hub area. The player can either pick the lock (100 Lockpick required) or ask Branchtender Cypress for the key.

Resistance in the Oasis Caverns mostly consists of Mirelurks, Mirelurk Kings, along with the odd Radroach. NPCs will have trouble following through the mess of underwater tunnels, so they should be left outside. There's plenty of decent loot to be had in the tunnels, so search extensively. Notable loot inside the Sunken Chambers includes a D.C. Journal of Internal Medicine (In a box by the table, underneath a baseball glove), a couple Stealth Boys, and a single Pre-War Book. If you need Crutches for the Railway Rifle, there's a pair on the bed. There is also a Silenced 10mm Pistol on the table and two Cherry Bombs in a crate. After getting the loot, continue to the next pool of water where there is a Mini Nuke underwater in the center of the pool and two stimpaks by skeleton futher ahead. In the next chamber straight ahead, are two ammo boxes with missles and flamer fuel (flamer fuel in an easy locked box and missles in an average locked box). There is a Missile, Blood Pack, RadAway, Purified Water and a Stimpak in the north-east of the area lying next to a skeleton. Other than that there is no notable loot except a few Empty Soda Bottles, Tin Cans, Milk Bottles and Small Ruined Books.

In order to advance, going underwater is necessary at times, so if it doesn't look like there's a way through, try checking underwater. Near the end of the Sunken Chambers, a thumping will be heard. This is the sound of Harold's heart. When reached and interacted with, the options mentioned before will present themselves to the player. If the heart is destroyed, then the Barkskin perk will immediately be obtained from being exposed to the radiation. This perk grants an inherent 5% damage resistance.

Aftermath and rewards
A nearby door will lead into another cavern, which will lead back to the Grove, where either Birch or Laurel will be waiting depending on the choice made. If the heart was destroyed, Birch will be there, expressing regret over not listening to Harold. If the Sap or Liniment was applied, Harold may be spoken to, and will have some dialogue about the choice.

At this point, the Treeminders who supported the player's decision will supply him/her with gifts. The Treeminders may also be spoken to after this to get dialogue about said choice. Note that Sapling Yew will give Yew's Bear Charm if the Speech Check was passed, regardless of the choice made. She is also the only one who will give a reward if the heart is destroyed.

If the sap was applied...

 * Branchtender Maple will give the player Maple's Garb.
 * Branchtender Cypress will give the player a Missile Launcher and one or two Missiles.

If the liniment was applied...

 * Bloomseer Poplar will give the player Poplar's Hood.
 * Branchtender Linden will give the player Linden's Outcast Power Armor.

If the heart was destroyed...

 * No additional gifts will be granted (again, with the exception of Yew's Bear Charm); but the Barkskin perk arguably makes up for it.

The Damp Cave
You can access this cave by a door near Harold's heart or SE of Harold is a cave. The cave is noticeable by a white rock above the water. The entrance is under water and is locked by an easy lock.

Inside the cave there could be Mirelurk Kings, Mirelurk Hunter or standard Mirelurks, dependent on the PC's current level.

Loot: When you come back above water the second time, on your left will be:
 * 1 Buffout
 * 1 Box of 10mm Round
 * 1 10mm Pistol
 * 1 Nuka-Cola Quantum
 * 1 Stimpak
 * 2 Nuka-Cola
 * 1 Conductor and 1 Lunchbox

At the South-East side of the cave ( just straight ahead ):
 * 1 Ammunition Box Locked Very Easy
 * 1 Sniper Rifle Value 31 (20% CND)
 * 1 Stimpak
 * 1 RadAway
 * 2 Fission Battery
 * 1 Med-X
 * 1 Combat Knife Value 14 (35% CND)

On a glowing ledge there is a missile, a paint gun, and a leaf blower that you cannot knock off the ledge with frag grenades. The missile and paint gun came down first try. To get onto the ledge, you have to go through a door located in the southern edge of the room in which Harold's heart is located. (End of quest has a back door shortcut. This is that ledge.) It is advised to bring a Radiation Suit and Rad-X, because the cave is flooded with irradiated water.

Bugs

 * After talking to Harold/Bob, if you return and talk to him again after he tells the PC he needs time to say goodbye to Bob, the PC may become trapped in a circular conversation with no way to exit but reset
 * If Tree Father Birch is killed, all of Oasis will turn hostile against the player. However, this happens even if the player wasn't the one to kill him (e.g. an enemy was lured over before starting the quest). Strangely, the same won't happen if Branchtender Maple is killed in this fashion.
 * If you enter Oasis, but leave before the ritual is complete, Father Birch could mysteriously vanish. This makes it impossible to complete the quest without burning Harold. You can get him to come back if you wait in a place where he goes everyday (his chair, for example) for 24 hours. Once you've stopped waiting, he will appear in front of you and you can continue the quest normally.
 * Leaving before the ritual can sometimes cause Father Birch to appear in random locations (e.g., in the Galaxy News Radio Station)
 * If the player does not stand across from Tree Father Birch during the ritual, it may not complete correctly, effectively forcing the player to reset.
 * Occasionally, Oasis will be locked for no given reason. If this happens after starting the quest but before finishing it, it will be impossible to complete. This will also effectively cause Birch's Sap and Laurel's Liniment to permanently take up weight in the player's inventory. On very rare occasions, it is even possible for the door to lock while INSIDE Oasis, although in that instance, it is possible to escape if Tree Father Birch is killed and the Key to Oasis is retrieved from his body, otherwise another escape is to kill Harold/Bob gaining bad karma and then the Oasis door will be unlocked (you will be unable to collect the item rewards due to Oasis becoming hostile.)
 * When approaching Birch and Laurel after seeing Harold, if the player gets close enough so they can hit them with a melee or unarmed weapon in V.A.T.S., but not close enough to trigger the conversation, and tries to attack either in such a fashion, the first two lines of their argument will take place in slow motion with a shaky camera.
 * When approaching Birch and Laurel after seeing Harold, it's possible to get close enough to speak with them, but not close enough to trigger their conversation. If this is done, they will immediately go into their dialogue about their tasks. The trigger point still exists, though, and stepping near where it was will trigger the conversation (even if they're walking as they do so).
 * In Laurel's case, the two will immediately walk off after her dialogue is over. Birch's dialogue will never happen, so the player cannot get out of the control loss that happens when the conversation starts, making it impossible to proceed. Speaking with both has a similar effect.
 * However, if Birch is spoken to, the entire conversation can be effectively skipped. If it is triggered after his dialogue is over, Laurel will start saying her lines, and after a few moments, approach the player to give her dialogue. Control will be regained afterward, with the conversation continuing as the two walk off. It should be noted that if Laurel speaks with the player in this fashion when he/she has not triggered the conversation, there will again be no way out of it.
 * 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 re-enter the cave.
 * The ledge in Damp Cave leading to Harold's heart can be reached from The Grove's side. Inside, there is a Mirelurk King and two Mirelurks waiting. Kill the Mirelurk King and one of the Mirelurks, and get the remaining Mirelurk's attention. Then, scale the cliff near the door to the next area, starting from the rocks on the right side (not the little shoreline just below it). Usually, the Mirelurk will mysteriously teleport on top. Get its attention again if it was lost (i.e. a Stealth Boy was in use), get as close as possible, then go into V.A.T.S. and try to hit it. The player character will teleport onto the cliff as well to attack the Mirelurk. However, the door will require a key to open (neither the Key to Oasis Caves nor Key to Oasis will unlock it).
 * The Sap and Liniment may not weigh anything until either is applied.
 * Sometimes, Sapling Yew will not offer you her charm, even if the Speech Check/Perk Check is completed. Also, sometimes completing quest at night (coming out when most are asleep) Sapling Yew cannot be found (and no bear charm); however going back to Oasis during daytime (tried after 7:00 AM) solves the problem, since Sapling Yew will be there and offers a speech option about her present for you). }}
 * If the Treeminders are angered through dialogue, the cave may still be entered with 100 Lockpick. The heart can still be reached, and the Barkskin perk can still be obtained. Strangely, the Sap or Liniment can be applied despite not having either. Harold will react accordingly through dialogue to this. However, as the only way to complete the quest is to speak with Birch/Laurel, and they will only say to leave when spoken to, again, Harold must burn if the quest is to be completed. If the Barkskin perk is obtained, Harold will not be able to be burned, leaving the quest permanently incomplete.
 * If Sydney is in your company, it may glitch so she will not exit the main gate of Oasis after the mission is completed. Untested as to whether or not this is due to leaving her outside the caves. This is easily resolved by simply fast traveling to another location.
 * Occasionally when targeting the Mirelurk King in V.A.T.S the game gets stuck in V.A.T.S allowing you to target but not leave into normal play. If you don't have enough AP to select a target the game must be restarted. This will also happen with Mirelurks, like the first one you encounter.
 * After leaving the Oasis caves, regardless of how you handled Harold's heart, either Laurel or Birch will be inside Harold's area and the gate will be locked and require a key, and they will not come out. The gate out of Oasis will also be locked and will be red; the only way to escape is to kill Birch, if you sided with Laurel, and use his key to escape, but this will fail the quest as all the residents of Oasis will turn hostile. You can get around this by going through the Damp Cave in the chamber with Harold's heart. The Damp Cave leads right to The Grove. You will be able to speak to Birch or Laurel and completed the quest, but you will have to kill them for their key to escape, as both the door to the Grove and the door out of Oasis will remain locked. Killing either will turn all of Oasis hostile and you will be unable to get the rewards from the Treeminders.
 * Your crosshair may freeze and not be able to move if you enter the cave before you start the quest. To fix this, start the quest and drink the sap. Also, as an added tip, you may want to use V.A.T.S to move the crosshair so that you may speak to Tree Father Birch
 * A few of the Mirelurks will be glitched in the water if you kill them there. Rarely this will cause leaving the caves impossible causing your Xbox to freeze after doing what you decided to Harold's heart. To fix simply drag them out of the water.
 * Sometimes when going through the path with the beds to the chain link fence, the game will lock your PC Being unable to Move, Use Pip-Boy, and Shoot Guns. All you can do is look around, crouch and change view as if you’re sitting on a chair style. To Fix the PC Version Press the ~ Key (or Equivalent) to enter the console and enter the command "tcl" without the " this will state Collision off then walk to the gate, make sure you are above the floor and enter console again and enter the command again to restore clipping. You should be able to now open the gate!
 * After the conversation between Laurel and Birch, the player may not regain his/her ability to do anything besides look around in one place like they should. This can be fixed by going into the console on PC (~ key) and typing "EnablePlayerControls" and pressing enter.
 * If the player insults the Tree Father after the conversation between Birch and Laurel, the player can no longer continue the quest, as no one will hold a conversation with them. Not only that, but about 4 hours after insulting him if the player remains in Oasis everyone shall turn hostile towards them.
 * If you go through the caves and come out the other end and miss interacting with the heart altogether the game can freeze if you try to go back in.
 * Crash: Some PC users may experience a CTD (Crash to Desktop) when they attempt to initiate a dialogue with Harold the talking tree. Upon selecting any of the three dialogue options, the game will crash when Harold tries to say his second part of the dialogue. It has been discovered that the audio files relating to that part of the dialogue are corrupted, and a user-made fix has been released here. If you do not want to visit that link, simply download this file and install it as you would a normal addon. Then retry the dialogue.
 * Birch may not begin the purification ritual after the PC drinks the sap.

Behind the Scenes
Oasis is a reference to the Oases of the Middle East. Where trees and grass drow out of the desert, because they are fed by underground reservoirs.