Stop Gizmo.

Stop Gizmo is the main Junktown quest in Fallout.

Synopsis
Control over Junktown is split between Killian Darkwater and Gizmo. The former is the town's mayor, sheriff, and primary trader; the latter the local oligarch, controlling the town's casino and boxing venue. The two men are perpetually at odds and they would rather see each other dead than compromise. Things come to a head when the Vault Dweller enters the town, getting caught up in local politics the moment they step through the door of Darkwater's...

Assassination

 * In order to start the quest, the player needs to talk to Killian in his shop. After exiting dialogue, Kenji will enter the shop, shout "Gizmo sends his regards" and start shooting at Killian with a hunting rifle. The player needs to attack Kenji at least once. Once Kenji is dead, the player receives 400 XP and Killian will talk to them about obtaining proof of Gizmo's involvement.
 * Obviously, if the player ignores Kenji, the gunman will be killed by Killian and the guards (unless the player deliberately robs Killian of his stimpak supply and Kenji gets a few lucky shots in), Darkwater will not initiate the conversation. In this case, the player can still go and talk to Gizmo, tell him that the assassin failed, and get hired to kill Killian. If the player admits as such to Killian, mentioning that Darkwater should do something about it, Killian will offer the next part of the quest as normal.

Entrapment

 * Killian will immediately talk to the player if they're close enough once combat ends and ask them to provide proof that Gizmo was really behind the job.
 * Refusing to help will result in -1 Karma and Killian locking the player up until midnight, to prevent Gizmo from learning of Killian's plan. The player can come peacefully, landing in jail where they can rest until 00:00 for Andrew to let them out. Gizmo and Izo will be killed by Killian in the meantime and the casino shut down. If the player resists arrest, Killian and the guards will attack.
 * If the player accepts, they will receive a bug and tape recorder. Characters with less than 4 Intelligence are not capable of coherent speech and cannot accept the quest.
 * Gizmo is located at the back of his casino. To obtain his confession, the player must either:
 * Use steal to plant a bug on Gizmo (it's not necessary to talk to him then),
 * Have the tape recorder in inventory, then talk to him. Then it's a simple matter of getting hired to kill Killian (by following the hypothetical dialogue option).
 * The player then has to return to Killian to collect the reward (the same regardless of option).
 * Killing Gizmo without delivering the confession and then organizing a take down will result in the player being expelled from Junktown (Killian will send the player to Lars, who will promptly boot them out of the town).

Elimination

 * To participate in the shoot-out, the player has to talk to Lars, the town guard near the entrance, and agree to come with him to take Gizmo down. Then it's a simple matter of gunning Gizmo and Izo down. The player is teleported to Junktown's entrance automatically after combat ends, but can return to the casino to loot the bodies.

Reward

 * A total of 1 500 XP: 400 for killing Kenji, 500 for obtaining proof of Gizmo's involvement, and 600 for killing Gizmo.
 * +2 Karma for killing Kenji (+3 if the player delivers the killing blow).
 * One of the following for obtaining proof:
 * 5 stimpaks,
 * doctor's bag,
 * leather armor,
 * shotgun with 100 shotgun shells.
 * 500 caps for killing Gizmo.

Bugs

 * The quest frequently bugs out and remains active in the PIP-Boy.