Finishing Touches

Powering Up: Head to the El Dorado Substation (east of Black Mountain, west of El Dorado Dry Lake). Use the Override Module given by Yes Man to jumpstart the Lucky 38's reactor, granting control over the Securitron army. The NCR guards this substation and will attack on sight. Sneak in or disguise yourself as an NCR member. Inside, find the north-west Terminal, activate it, and use the Override Chip. Return to Yes Man at the Lucky 38. You will receive 500 XP and NCR Infamy for installing the Override Chip.

Keeping Freeside Calm: Before proceeding to Hoover Dam, ensure Freeside remains stable. Mr. House had contingency plans involving the Followers of the Apocalypse. Go to the Old Mormon Fort and speak with Julie Farkas. Exhaust her dialogue options; she can be convinced to support your cause without any skill checks. This will help maintain order in Freeside while you are at Hoover Dam.

Final Preparations: With Mr. House eliminated and bridges potentially burned with the NCR and Caesar's Legion, prepare for the final confrontation at Hoover Dam. Complete any outstanding quests, especially 'For Auld Lang Syne' for potential backup and to lower Arcade's trust requirements. Ensure your gear is repaired, and stock up on ammo and healing supplies.

Initiating the Final Battle: Talk to Yes Man at the Lucky 38 and tell him you are “ready to go to the dam.” He will present two options: power up Mr. House’s bunker at Fortification Hill to activate your Securitron army, or destroy the dam’s generators to negate its strategic importance. Choose to power up the bunker for a more beneficial outcome. You will receive another Override Module and a warning that you are at the point of no return. Select the “Let’s do this!” option to complete the quest 'Wild Card: Finishing Touches', unlock the 'Wild Card' Trophy/Achievement, and start the quest 'No Gods, No Masters'.