Fallout 3

Players start this quest as soon as they discover Oasis. Oasis can be found north-west of Clifftop Shacks. Random encounters with Wastelanders can also identify this location on the map. It is the only location with growing trees.



As soon as you enter, you will be approached by Tree Father Birch and put through a ritual. From here, you want to at least talk to five people:

*Harold, who most Fallout veterans will recognize from the prior two games, and asks the player to destroy his heart and let him die.
*Tree Father Birch, who will ask the Player to apply a sap to Harold's heart to stop his growth, in fear that the secrecy of Oasis and its location is what has kept it alive for so long.
*Leaf Mother Laurel, who will ask the Player to apply a liniment to Harold's heart in order to accelerate his growth, believing his gift should be shared with the rest of the wasteland.
*Sapling Yew, who after passing a Speech or Child at Heart check will reveal Harold's fear of fire.
*Branchtender Cypress, who will give you the key to the caves where you will find Harold's heart.

The caves can be accessed from the central area in Oasis, and lead on to the Sunken Chambers, where the player will find Harold's beating heart at the end.

From here, there are four paths the player can take.

Burning Harold
Harold wishes to die, and although he specifically requests that you don't, the easiest way to do this is to burn him alive. Set fire to him using any fire weapon (some explosive and energy weapons work, too), and watch him burn. This is the only method that does not require players venturing into the caves to find Harold's heart.

NORML RASTA MAN reminds us that although this is the easiest method of completion, it incurs a severe karma loss, and all the disciples will turn hostile to the player.

This also offers no reward, and although it is by far the quickest method of gaining the achievement, if players wish to take this path, I would recommend saving before hand and doubling back in order to gain some of the rewards offered along the other paths.

Note that you do not get item rewards until you have completed the quest and spoken to the relevant NPC, and that you need to have passed the speech check with Yew to gain her reward.

Destroying Harold's Heart
Method: Attack the heart with anything that does not involve fire.
Aftermath: Harold will die, and the disciples will accept your decision, feeling remorse for not having taken Harold seriously.
Rewards:
* Bark Skin Perk: 5% Damage Resistance
* Yew's Bear Charm: +10 to Speech while in inventory

Apply Birch's Sap
Method: Apply the sap to Harold's heart.
Aftermath: Oasis will stay a secret, and Harold will thank the player for not killing him, accepting how important he is to the lives of all that live in Oasis.
Rewards:
* Yew's Bear Charm: +10 to Speech while in inventory, given by Sapling Yew.
* Missile Launcher + 2 Missiles: given the player by Branchtender Cypress.
* Maple's Garb: a unique version of Oasis Robe, given by Branchtender Maple, offering +1 to Agility and +1 to Perception.

Apply Laurel's Liniment
Method: Apply the liniment to Harold's heart.
Aftermath: Harold will thank the player for not killing him, and his growth will eventually engulf the entire Capital Wasteland, turning the entire desert waste into an oasis.
Rewards:
* Yew's Bear Charm: +10 to Speech while in inventory, given by Sapling Yew.
* Poplar's Hood: a unique version of Oasis Druid Hood, given by Bloomseer Poplar, offering +1 to Agility and +10 to Sneak.
* Linden's Outcast Power Armour: a suit of Power Armour given to the player by Branchtender Linden, offering +1 to Strength, -1 to Agility, +5 to Big Guns and +10 to Radiation Resistance.

Links
Wiki page on the location: http://fallout.wikia.com/wiki/Oasis
Wiki page on the quest: http://fallout.wikia.com/wiki/Oasis_(quest)
Wiki page on Harold: http://fallout.wikia.com/wiki/Harold

Oasis is in the far north. This is an odd quest and for those who have played Fallout 1 and 2 you may recognize a character from that game. Basically there is a cult who worships "The One" without giving too much away you have to participate in a ceremony and then talk to "THe One". I had a hard time finding him mostly cuz I was blind but check out the tree in the middle of the area where you wake up in. THe one will ask you to enter a cave and destroy a heart. AFter this conversation go back through the gates back to the first area of the oasis. TAke the path on the left and you will overhear 2 people having a conversation. Both will propose and alternate ending to this quest. They will both give you materials to pour on the heart. Talk to the man behind the 2 who had this conversation and enter the cave. Just find the heart and make your decision. Then return to "The One"

REWARDS:
If you kill the heart you get the Barkskin perk(+5 Damage Resistance)
If you pour the solution the man gives you you will receive an armor (forgot what it was)
If you pour the solution the woman gives you, you will receive 2 pieces of armor a hood that gives you +10 sneak (and another bonus.. sorry don't remember exactly what it was) and you will also receive a unique outcast power armor.