Kings' Gambit

Kings' Gambit is a main quest in Fallout: New Vegas.

Detailed walkthrough
Once you have completed the quest Things That Go Boom, speak to Ambassador Crocker, who will assign Kings' Gambit. Crocker tells you about all the violence in Freeside being caused by the Kings. He gives you two options: solve the problem diplomatically, or kill Pacer, the main person responsible for the violence.

Option: Kill Pacer
If you have already talked to the ghoul Rotface, he may have given you tips, two of which include the fact that Pacer has a heart problem and too many drugs will kill him and another is he has a feud with the Van Graff family (If you have not talked to Rotface, you open this option by stealing Pacer's treatment records from Julie Farkas' filing cabinet in the Old Mormon Fort). This will add two optional objectives to the quest, one to kill Pacer by adding Psycho to his jet (requires 60 Medicine) and the other is to kill Pacer in a way that implicates the Van Graff family. You have to do this before his stash appears.

Method: Frame the Van Graff family (Jean-Baptiste Cutting's note)

 * 1) Examine Pacer's stash of jet which is disguised as a carton of cigarettes under his bed, (then try to take it, a prompt will appear stating that you should obtain a note to pin the blame on someone else), then return to Ambassador Crocker.
 * 2) Talk to Ralph at Mick & Ralph's and ask him to forge a handwritten note written to Pacer from Jean-Baptiste Cutting. (he will only do this if you have a high enough Speech skill [50] or if the Kings have accepted you, and if Rotface tipped you about the feud between Pacer and the Van Graffs)
 * 3) Go to Pacer's room (first room on the left, third floor of The King's School of Impersonation).
 * 4) Replace Pacer's stash of jet with the handwritten note.
 * 5) When Pacer checks his stash, he will immediately run over to the Silver Rush and get himself killed.

This method works even if you killed everyone in the Silver Rush building earlier. Just follow Pacer there after planting the note in his room and kill him yourself with a plasma or laser weapon to frame Van Graffs.

It is important to talk to The King before returning to Ambassador Crocker.

Method: Frame the Van Graff family (working as a guard)

 * 1) Start the quest Birds of a Feather.
 * 2) While working as a guard, when Pacer comes and talks to you, pick a fight with him by using hostile dialogue options such as the third option in the first dialogue and "Care to back that up?" in the second. This will make him hostile.
 * 3) Kill him with the energy weapon the Van Graffs issued you.

Doing this won't make the Kings hostile and will make you successfully complete both Kings' Gambit (since you killed him with an energy weapon while working for the Van Graffs) and Birds of a Feather (killing him doesn't make you fail this quest).

However, killing Pacer will break the quest line G.I. Blues, therefore it is recommended finishing that quest first.

Method: Frame the Van Graff family (planting energy weapon)

 * 1) Wait in or around Pacer's room until night time.
 * 2) Sneak into his room and pick his pocket, planting a plasma grenade or mine on him.
 * 3) Back up REALLY quickly.

Doing this will off Pacer in a way to frame the Van Graffs, so you'll still get the rewards from the Ambassador, and the Kings will not suspect you.

Note: You must first go back and talk to the ambassador (after you speak with Rotface) first before planting the plasma grenade/mine. Otherwise, Pacer will never go to sleep in his room.

Method: Spike the jet with Psycho
To complete this method, either speak to Rotface and give him caps until he tells you about Pacer's addiction or check the filing cabinet in Julie Farkas' wing of the Old Mormon Fort. You must also first speak with Ambassador Crocker and tell him your plan, which requires a [50] Medicine check. It will then add an optional quest to kill Pacer using his jet. Follow these steps: Note: killing Pacer in any way will immediately fail the quest G.I. Blues, so if you want a favor from The King, you need to finish G.I. Blues before you kill him.
 * 1) Go to Pacer's room (the first room to the left on the third floor of The King's School of Impersonation)
 * 2) Add the Psycho to the stash of jet under his bed (roughly between 8A.M. and 9P.M.). The stash is disguised as a carton of cigarettes, but it will only appear AFTER speaking with Rotface or looking through Julie Farkas's files (see above).
 * 3) Pacer will die by checking his stash in his room during the night (the earliest time he can be found in his room is about 7P.M.)
 * 4) Pacer will die immediately when he checks his stash.

Method: Just kill Pacer
Using an energy weapon to kill Pacer will allow you to accomplish this quest, however using any conventional weapons will result in failing the quest. If the latter is the case, you still get a reward (if you apologize) and are still allowed to move onto the next quest. If you wish to easily regain fame with Freeside, go to the Atomic Wrangler and talk to James Garret regarding spreading positive rumors about you in Freeside. You will have to pay more caps depending on how infamous you are.

Option: Solve diplomatically
If you haven't used your favor from G.I. Blues yet, you can use it to ask The King to stop the violence and turn the quest in. However, if you have already used it, the King will say no and you will have to return to Ambassador Crocker and tell him that the King will not stop the violence. Crocker will then give you two options (on top of the option to kill Pacer): Talk to Colonel Moore at the Hoover Dam or talk to Colonel Hsu at Camp McCarran.

Method: Colonel Moore

 * 1) Head to Hoover Dam and talk to Colonel Moore, she will tell you to tell the Kings to stand down or be destroyed and offers to send a squad to back you up.
 * 2) Anything you say to The King will cause him to refuse and a fight will break out, and you will fail the mission when you tell Crocker what happened. However you will not gain any Freeside infamy if you let the troopers do all the shooting, and you can get The King's unique suit and you even get a reward of 300 caps from Crocker if you apologize and you get to move onto the next quest. If you do not have Rex as a companion at this time he may be killed by the NCR and you won't be able to recruit him again.

Method: Colonel Hsu

 * 1) Go to Colonel Hsu at Camp McCarran and tell him about the situation in Freeside and he will tell you to offer the King support from the NCR.
 * 2) When you get back to the King, tell him the NCR have offered their support. If you are rude to him, his gang will open fire and you will fail the quest, although you will not gain any Freeside infamy if you let the troopers do all the shooting. He will also open fire if you just tell him to calm down, taking it as a challenge. You can get the King's unique suit and even get a reward of 300 caps from Crocker if you apologize and you get to move onto the next quest.
 * 3) If the player is polite, the King agrees to peace with the NCR, but Pacer will become angry and will attempt to stage a coup within the Kings, and he and a few Kings gang members will start a gunfight with the NCR troopers, the King, and the Kings loyal to him. Pacer and the men who side with him are killed and the King goes ahead with peace between the Kings and the NCR.

After this, return to Crocker.

Note: if you attack Pacer or any other Kings, even after they turn hostile and open fire, it may result in a gain of infamy with Freeside and both groups of Kings as well as the King himself turning hostile. The best way to avoid this is to let the NCR troopers and any companions do the shooting, which results in no infamy gained for the player. Pacer and his men are heavily outnumbered by the NCR troopers alone, meaning there is little chance the King will die in the gunfight. Additionally, there was originally going to be an opportunity to pass a Speech check of 75 and talk Pacer down from staging the coup. This was cut from the game and can only be restored through the use of mods on the PC version of the game.

Reward
The player will be rewarded with 1300 XP, 600 caps and NCR fame. With a 60 Barter you gain another 200 caps. In addition, the quest For the Republic, Part 2 will begin. The player will get neither of these if you just kill Pacer.
 * Received 1200xp and had an option (with a Barter skill of 60) to ask for more caps (200). Diplomatic solution, using a favor from The King.
 * Received 1200xp, received 600 caps and had an option (with a Barter skill of 60) to ask for more caps (200). Spike the jet with Psycho solution.

Quest stages
{{Quest stage table }}
 * stage1   =10
 * desc1    =Kill Pacer in a way that implicates someone other than the NCR, or talk The King into ceasing hostilities with the NCR
 * stage3   =11
 * desc3    =(Optional) Kill Pacer in a way that implicates the Van Graff family.
 * stage4   =12
 * desc4    =(Optional) Kill Pacer by adding Psycho to his jet.
 * stage5   =13
 * desc5    ={Optional) Perform tasks for the King in order to get on his good side
 * stage6   =20
 * desc6    =Return to Ambassador Crocker with news of Pacer's death.
 * status6  =finish
 * stage7   =40
 * desc7    =Return to Ambassador Crocker with the news that the King has agreed to cease hostilities.
 * status7  =finish
 * stage8   =41
 * desc8    =Return to Ambassador Crocker with the news that the King will not curb the violence in Freeside.
 * stage9   =50
 * desc9    =Speak with Colonel Moore at the Hoover Dam for further instructions regarding the situation in Freeside.
 * stage10   =51
 * desc10    =(Optional) Speak with Colonel Hsu in Camp McCarran for further instructions regarding the situation in Freeside.
 * stage11  =60
 * desc11   =Go to the Kings' School of Impersonation and deliver an ultimatum to the King, backed by a squad of NCR troopers.
 * stage12  =65
 * desc12   =Help the NCR Troopers kill all the Kings.
 * stage13  =70
 * desc13   =Go to the Kings' School of Impersonation and offer the King official NCR support if he ceases hostilities.
 * stage14  =75
 * desc14   =Stop Pacer from ruining the deal between the King and the NCR.
 * stage15  =80
 * desc15   =Return to Ambassador Crocker and report that the King has agreed to the ultimatum and will cease hostilities.
 * status15 =finish
 * stage16  =81
 * desc16   =Return to Ambassador Crocker and report that the Kings have been wiped out.
 * status16 =fail
 * stage17  =90
 * desc17   =Return to Ambassador Crocker and report that the King has accepted Colonel Hsu's pledge of NCR support.
 * status17 =finish
 * stage18  =91
 * desc18   =Return to Ambassador Crocker and report that the Kings have been wiped out.
 * status18 =fail

Behind the scenes

 * In chess, the Kings' Gambit is an opening strategy where a pawn is sacrificed in exchange for rapid development and control of the center.
 * It was believed that Elvis Presley died of a drug-induced heart attack due to underlying heart problems, much like how Pacer dies if his drug stash is tampered with.