For Auld Lang Syne

For Auld Lang Syne is a companion quest

Initiating the quest
This quest is initiated by Arcade Gannon, when he realizes that his old friends from the now-defunct Enclave could make a difference in the second battle for Hoover Dam.

The quest is triggered by having Arcade as a companion, gaining his trust, and having progressed to one of the main storyline triggers (even if he wasn't recruited at the time it happened). If the player character is following the Caesar's Legion quests, equipping a suit of NCR armor will allow Arcade to be recruited despite high reputation with Caesar.

Storyline triggers
The specific point in the story that will trigger the quest varies based on whether the player character has gained Arcade's approval (see the section below) and which main quest line the player character has moved forward with.

If Arcade approves of the player character (at least two "trust" points gained via the methods below), he will offer the For Auld Lang Syne quest if one or more of the following conditions are met (regardless of having Arcade recruited at the time they happened):
 * The House Always Wins, part V is active, and the player character reports back to Mr. House that the Brotherhood of Steel bunker has been wiped out.
 * Wild Card: Change in Management is active and the player character installs Yes Man into the Lucky 38 mainframe. Yes Man then needs to be installed (and the quest therefore completed) for Arcade to make his request.
 * For the Republic, Part 2 is active and the player character reports back to Colonel Moore that Mr. House has been killed or disconnected from his mainframe.
 * Wild Card: Finishing Touches is active and the player character installs the override chip in the El Dorado substation.

Note: Arcade will not offer this quest in response to any Caesar's Legion quest, though as it is possible to work on multiple main quests simultaneously, it is possible to trigger the quest while still doing work for Caesar. To do this, achieve an 'accepted' status from Caesar's Legion (and the NCR, in order to prevent them from becoming an immediate enemy, but achieving a favorable reputation with Caesar's Legion is much harder) and install Yes Man. Both Don't Tread on the Bear! and Beware the Wrath of Caesar! will activate, but neither will give a shunned reputation. Note that if traveling far enough along the main quest lines to offer the Boomers' help to either side, the two respective warning quests will activate, and installing Yes Man will cause the Courier's reputation to drop to vilified. To avoid all repercussions from the NCR, this means finishing the quests Render Unto Caesar through Part 2 (Kill Mr. House then report back to Caesar before installing Yes Man), The Finger of Suspicion, killing Benny in the arena, and defeating all of the competitors in the arena (all give Legion fame).

If the player character convinces the Remnants to fight for Caesar, however, or travels to the Legate's camp to start the assault on Hoover Dam, Arcade will quit. Even when approaching the Remnants bunker, he will not activate the quest.

Gaining Arcade's approval
Arcade keeps a running tally of trust "points" the player character has earned by doing things he likes. To get him to offer this quest early (or at all, if the player character is supporting the NCR or Mr. House), the player character must earn somewhere around 5 points either by going places that trigger positive memories of the Enclave, flattering him, doing smart things (passing Intelligence checks), or doing things that are good for the Followers of the Apocalypse.

Not every place or event that Arcade comments on represents an improvement of his approval rating of the player character. Arcade also has a running tally of "dislike" points, but they do not figure into this quest. They are only used to trigger a warning about the player character's behavior, and eventually cause Arcade to leave the player character permanently. See Arcade's page for more about "dislike" triggers.

The following is a comprehensive list of events that earn trust "points" while traveling with Arcade as a companion. In certain situations, different amounts of points can be earned, depending on which response is given in dialogues: Though Arcade comments on energy weapons in the Silver Rush, his approval does not increase.
 * Traveling to a few places in the Mojave Wasteland with Arcade will trigger a comment and gain the player character points:
 * 1 point for traveling with Arcade to the crashed vertibird southwest of Camp Searchlight (the approval does not increase until Arcade comments on it).
 * 1 point for traveling with Arcade into the REPCONN Headquarters building (the approval does not increase until Arcade comments on the company)
 * Traveling to the Fort with Arcade triggers a dialogue with the Courier inquiring why they are there.
 * 2 points for saying, "Let's just listen to him, figure out what he's up to, and get out."
 * 1 point for saying, "I just want to hear Caesar out."
 * 1 point for saying, "With how messed up New Vegas is, do you really think Caesar has nothing to offer?", followed by, "I'm just trying to be open-minded."
 * All of the above comments will work even if Caesar has been killed previously.
 * Although, if Caesar is left alive and Arcade is the active companion, there are more like points to gain after speaking with Caesar in his tent.
 * 2 points for passing an Intelligence check of 8 saying, "I don't think either of us can fully understand what he and the tribes have gone through."
 * 1 point for saying, "He's a madman. What did you expect?"
 * Speaking to Thomas Hildern about anything at all (any conversation that ends with Hildern saying, "Yes...Goodbye." or "Wrong turn?...") with Arcade along will cause Arcade to start a conversation afterward about Hildern and his motives (one time).
 * 2 points for saying, "Good thing there are still people like you around."
 * 1 point for saying, "I'm sure he means well."
 * During the quest That Lucky Old Sun, when the player character first speaks to Fantastic or gets to the mainframe, Arcade will spontaneously suggest that the power should be directed to Freeside and Westside.
 * 1 point for saying, "Of course."
 * 1 point for saying, "Why not to the whole area equally?", then passing an Intelligence check of 7, saying, "Redundancy. If Caesar takes the dam and cuts off power, it will be chaos all over New Vegas." when Arcade asks why.
 * Note that it is not necessary for the player character to do what Arcade wants; the trigger is the pre-diversion dialogue, not the action of diverting the power. This conversation also won't trigger if the player character has already entered the terminal room and chooses to recruit him afterwards right before they make their decision.
 * There are several triggers associated with the quest The White Wash:
 * 1 point for saying, "If you say so. I'm not arguing." when Arcade mentions that he's heard about Anderson, if the player character visits Westside with him after having already completed The White Wash without him along.
 * 2 points for completing The White Wash by blaming the problem on the Scorpions and letting Tom Anderson go (the approval does not increase until Arcade comments on it).
 * 1 point for completing The White Wash by getting Tom Anderson to turn himself in with a fake story about fighting over Dazzle, but letting Westside Co-op continue to have the water (the approval does not increase until Arcade comments on it).
 * 1 point for passing an Intelligence check of 7, saying, "You're assuming a motive without evidence. Please be rational." when Arcade gets mad about killing Tom Anderson at the end of The White Wash (This only happens if the player character kills Tom Anderson).
 * 1 point for saying, "It's cleaner this way, without bringing NCR in. No connecting Anderson back to the locals," in answer to Arcade's follow-up question to the above, asking why the player character killed Anderson.

Recruiting the Remnants
When the quest triggers, Arcade will approach the player character and ask if they can spare a moment to talk. Arcade tells them that he would like them to help him convince some of his old Enclave buddies to help the NCR fend off Caesar's Legion at Hoover Dam. If the player character agrees, the quest begins.

The player character must recruit five old members of the Enclave, known as the remnants, to come to a meeting to discuss the battle at Hoover Dam. If any of the five is already dead, the quest cannot be completed and will be failed. Each of them has a conversation tree and some will raise objections, but all can be convinced to come. Each of them will give the player character a single word of the five-word passphrase that opens the Remnants bunker, where the meeting will be held.

The five Enclave Remnants are:
 * Daisy Whitman, found in or near her hotel room in Novac, gives the word "Dear."
 * Cannibal Johnson, found in Cannibal Johnson's cave, gives the word "old."
 * Doctor Henry, found in the main building at Jacobstown, gives the word "friends."
 * The quest Guess Who I Saw Today will need to be completed before Henry will agree.
 * Orion Moreno, found in his house north of NCR sharecropper farms, gives the word "remember."
 * Judah Kreger, found in Westside, gives the word "Navarro."

Important note: After asking each of the Remnant members to join, the player character should wait for Arcade to approach the player character and make a comment about each one in order to set the quest flags properly. For each of the five recruits, the player character can give one of two responses: a response that talks about how people cannot (or should not) shake their past or a response that suggests that people should let go of the past, which helps Arcade make a decision later in the quest. If most of the responses suggest that people should let go of the past and forge a new future, he will be inclined to stay with the Followers of the Apocalypse and not fight at Hoover Dam, and if most of the responses suggest that people can't or won't change who they are, he will be inclined to join the fight.

Meetup at the bunker
Once all five of the remnants are convinced, the player character must go meet with them at the Remnants bunker. The five words given to the player character make the phrase "Dear old friends, remember Navarro," which will open the main door.

Upon entering the bunker, the player character must head to the briefing room in the back and talk to Judah Kreger. He will ask whether the player character wants them to aid the NCR or Caesar's Legion. If the player character is siding with Mr. House or angling for an independent New Vegas, then siding with the NCR for the battle of Hoover Dam is the right choice.

Siding with the NCR
If the player character chooses to ask them to side with the NCR, Orion Moreno leaves the room. He is found just outside the briefing room in the hangar. He will talk about his hatred of the NCR and will refuse to fight for them. If the player character has a Speech skill of 80 or has Wild Child reputation with the NCR, Orion can be convinced to participate in the attack, but otherwise he will attack the player character and must be killed.

The player character can then return to the briefing room. Judah will recommend talking to Daisy for power armor training. If Orion's armor was not picked up after killing him, then Daisy will give the player character her power armor, as she says it makes the cockpit "too cramped" if she is wearing it.

Siding with the Legion
If the player character asks them to side with the Legion, Cannibal Johnson and Arcade Gannon will leave and there is no way to convince them to stay. The player character can then talk to Orion Moreno for training in power armor. Moreno will give the player character Johnson's suit since he will not be using it.

Wrapping things up
Judah will ask the Courier to leave while they plan their attack. The player character will receive 500 XP and the quest ends.

If the player character convinced the remnants to fight for the Legion, Arcade will approach and accuse them of being crazy and/or a sociopath, then permanently leave as a companion.

If the player character convinced the remnants to fight for the NCR, Arcade approaches them and asks if they think he should join the remnants in the battle for Hoover Dam. The player character can suggest a path, but if that path contradicts the implications given earlier during the conversations, they must pass a Speech check of 80 to convince Arcade to choose a different path.

Arcade will then tell the player character that there is something he has to do, and he will give them all the gear he is carrying for them and run off. A short time later, he will come back with the Gannon family Tesla armor. If he plans to fight at Hoover Dam he will be wearing it and tell the player character that he cannot turn his back on his family and his past. If he plans to go back to the Followers, he will give the player character the armor and tell them to use it well during the fight.

Either way, he will then go away and will be non-recruitable for the rest of the game. If he chooses to remain with the Followers he will go away (not respawn) and if the player character follows him, eventually end up in the Lucky 38 suite with no possible option of recruiting him again. If he chooses to fight, he will be in the visitors center at the dam assisting the heavy troopers against the Legion.

Exploit for keeping Arcade Gannon as a companion
It is also possible to complete For Auld Lang Syne, even in the Legion's favor, without losing Arcade as a permanent companion. Simply tell Arcade to wait at the Lucky 38 after recruiting the remnants, but before entering the bunker. Arcade should still be waiting at the Lucky 38 upon finishing the quest. Note that using this exploit results in the Gannon Family Tesla armor becoming unobtainable, and Arcade Gannon's ending will be absent, unless he is sold to the Legion as a slave at a later point.

Behind the scenes
The name of the quest is a reference to the Scottish poem and song "Auld Lang Syne".