Stop Gizmo

Take Revenge on Gizmo is a side quest in Fallout.

Quick walkthrough

 * 1) Get Gizmo's confession.
 * 2) Deliver it to Killian.
 * 3) Go with Killian to kill Gizmo.

Detailed walkthrough
To complete this quest, the Vault Dweller first needs to get Gizmo's confession. Once delivered, Killian Darkwater will offer the Vault Dweller the option to join him in killing Gizmo. Should the Vault Dweller accept, they will be directed to Lars. Once spoken to, the Vault Dweller will be immediately transported, together with Killian and Lars, to Gizmo's office.

Gizmo and his bodyguard Izo will immediately attack.

Rewards

 * 600 XP
 * 500 bottle caps