Oasis (quest)

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

The ritual
When the player character approaches Oasis, Tree Father Birch will ask that they follow him, saying that "He" has summoned them. If agreed to, Birch will unlock the gate to the village and lead the player character to an outdoor hut. Birch explains that he is the leader of the Treeminders, and that "He" has summoned the player character 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 character drink a sap in a ritual to purge them of all evil that might be inside, so that "He" may go unharmed.

After the ritual, the Lone Wanderer 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 ask instead to either suppress or expand Harold/Bob's fertility.

To the 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 Wanderer 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. If this is done, negative Karma will be received and all of Oasis will become hostile.

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

Regardless of what the player character chooses to do to Harold's heart, speaking with Sapling Yew beforehand is recommended. If she is asked about her "god", a Speech check will become available, revealing Harold's fear of fire. If the Speech check is passed and the player character chooses not to burn Harold down to complete the quest, she will give them Yew's bear charm after completion of the quest. As an alternative, the Child at Heart perk can be used to guarantee success.

Siding with Birch
 * Speak with Branchtender Maple before entering the caves and ask her about how she ended up in Oasis. She will tell 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.

Siding 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 he 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.

Siding with Harold
 * There is no need to speak with anyone prior to entering the caves, with the exception of Sapling Yew.

Burning Harold
 * As is stated above, Harold is afraid of fire, and can be killed with almost any fire based weapon. The flamer, heavy incinerator, plasma rifle, missile launcher, Nuka-grenade (does not even have to detonate, just hit him), plasma grenade, mini nuke, or Shishkebab will all work on him. Once on fire, he will roar loudly and shake violently until dead. This will cause a Karma loss, and all of Oasis will immediately become hostile.
 * The following weapons do not set Harold on fire: the Firelance, frag mines, plasma mines, and the Burnmaster.

Into the caves
The main entryway to the cave system is in the main Oasis hub area. The lock (100 lockpick required) can be picked or Branchtender Cypress can be asked for the key.

Resistance in the Oasis caverns mostly consists of mirelurks, mirelurk hunters, and mirelurk kings (level dependent), along with the odd radroach. 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 of Stealth Boys, and a single pre-War book. If needing crutches for the railway rifle, there is 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 a skeleton further ahead. In the next chamber straight ahead are two ammunition boxes with missiles and flamer fuel (flamer fuel in an easy locked box and missiles in an average locked box). There is a missile, blood pack, RadAway, purified water, and a stimpak in the northeast of the area lying next to a skeleton.

In order to advance, going underwater is necessary at times, so if it does not 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 character. 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, where he regrets being selfish.

At this point, the Treeminders who supported the player character's decision will supply them with gifts. The Treeminders may also be spoken to after this to get the 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.

Sap applied

 * Branchtender Maple will give the player character Maple's garb.
 * Branchtender Cypress will give the player character a missile launcher and two missiles.

Liniment applied

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

Heart destroyed

 * The Barkskin perk is rewarded.

Sapling Yew

 * Sapling Yew gives the player character her charm if the Speech check was passed prior to the quest completion, or if the speech check is failed, having the "Child at Heart" perk will unlock the dialogue to get Yew's charm. (This increases the one's Speech by 10 permanently.)

The sunken chambers
The sunken chambers are the second cave-system one enters. After entering the sunken chambers, walk until one turns left, do so, and continue forward until coming across a table.
 * One pre-War book on top of the trunk next to a box of darts.
 * One D.C. Journal of Internal Medicine left from the table in a crate under a baseball glove.
 * One Stealth Boy on the table along with 1 silenced 10mm pistol and 10mm ammo.

Into the dead center of the irradiated pool water:
 * One mini nuke
 * One Mentats
 * Two Stimpaks
 * One Combat Knife

As you continue the road (near the skeleton):
 * One Stealth Boy on top of 2 ammo boxes
 * One Chinese assault rifle

Just as you get towards Harold's heart, turn left instead of right (next to a skeleton):
 * One Purified water
 * One RadAway
 * One blood pack
 * One missile
 * One stimpak

The Damp Cave
One can access this cave by a door near Harold's heart or southeast of Harold is a cave. The cave is noticeable by a white rock above the water. The door to the entrance is underwater and can be opened with the Oasis cave key or a Lockpick skill of at least 25.

One can enter the cave from Harold's grove, but it is rather meant to be a quick exit from the rest of the cave system. One cannot proceed from here to the rest of the caves, as there is a high ledge in front of the exit to them. Furthermore, entering from the submerged entrance requires swimming past a couple of mirelurks to solid ground before one can fight them.

Inside the cave, there could be mirelurk kings, mirelurk hunter, or standard mirelurks, dependent on the player character's current level.

Upon returning back above water the second time, on the left will be:
 * One Buffout
 * One Box of 10mm rounds
 * One 10mm pistol
 * One Nuka-Cola Quantum
 * One stimpak

At the southeast side of the cave (just straight ahead):
 * One ammunition box locked very easy
 * One sniper rifle valued 31 caps (20% CND)
 * One stimpak
 * One RadAway
 * Two fission batteries
 * One Med-X
 * One combat knife valued 14 caps (35% CND)

Behind the scenes
Yew said that "to judge the living and the dead" during the ceremony is a reference to the Apostles' Creed.

Bugs

 * Birch refers to the female Lone Wanderer as a male during the purification ceremony.
 * After talking to Harold/Bob, if the player character returns and talks to him again after he tells them he needs time to say goodbye to Bob, they may become trapped in a circular conversation with no way to exit but reset.
 * If one enters Oasis, but leave before the ritual is complete, Father Birch could mysteriously vanish. This makes it impossible to complete the quest without burning Harold. The player character can get him to come back if they wait in a place where he goes every day (his chair, for example) for 24 hours. Once the player character has stopped waiting, he will appear in front of them and the quest can continue normally.
 * Sometimes, Sapling Yew will not offer her charm, even if the Speech check/perk check is completed. Also, sometimes completing the quest at night (coming out when most are asleep) Sapling Yew cannot be found (and no bear charm); however completing the quest during daylight (tried after 7:00 AM) or waiting until the sun rises solves the problem. It may also be solved by speaking to Sapling Yew before going to the caves and asking her about his secret.
 * Sometimes, Bloomseer Poplar will not offer Poplar's hood if the player character has applied Laurel's liniment even if Leaf Mother Laurel says Poplar has a gift for them.
 * After leaving the Oasis caves, regardless of how one 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 one has sided with Laurel, and used his key to escape, but this will fail the quest as all the residents of Oasis will turn hostile. One 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. The player character will be able to speak to Birch or Laurel and complete the quest, but they 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 one will be unable to get the rewards from the Treeminders.
 * Sometimes when going through the path with the beds to the chain-link fence, the game will lock the player character, being unable to move, use the Pip-Boy, or shoot guns. All that can be done is look around, crouch, and change the view as if sitting on a chair. 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 to be above the floor, and enter console again and enter the command again to restore clipping. One should be able to now open the gate! To fix this on a console, load a saved game from prior to the argument between Laurel and Birch and then make sure to see their argument and speak with them while they are still near the chain-link fence. This bug may occur because there is a point near the chain-link fence where the player triggers the scene in which Laurel and Birch argue. If Laurel and Birch leave this trigger point without the player character seeing them argue, the trigger point may remain active and lock the player character when they approach. Load a saved game and while Laurel and Birch are still close to the chain-link fence, walk towards them and trigger the scene with their argument. The trigger point should then deactivate and no longer lock the player character.
 * After the conversation between Laurel and Birch, one may not regain their 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 one goes through the caves and comes out the other end and misses interacting with the heart altogether the game can freeze if one tries to go back in.
 * Birch may not begin the purification ritual after the player character drinks the sap.
 * The other Treeminders may also be spoken to after the argument 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.