Second Battle of Hoover Dam

The Second Battle of Hoover Dam is the conjectural name applied to the second offensive mounted by Caesar's Legion against New California Republic forces entrenched on Hoover Dam in 2282, as well as on the surrounding Mojave Wasteland.

Prelude
After the First Battle of Hoover Dam, Mr. House knew that as soon as either the NCR or the Legion became victorious at the Dam, they would turn their attention to New Vegas. In an attempt to stop this and allow the city remain under his control, he had Victor hire a courier to retrieve his platinum chip, a data storage device capable of upgrading the city's defense systems and activating a massive army of securitrons. This would give House the ability to single-handedly crush the Legion and intimidate the NCR into a retreat. However, the leader of the Chairmen, Benny, learned of this plan and ambushed House's courier outside of Goodsprings, shooting them in the head and leaving them for dead in a shallow grave, taking the platinum chip and throwing House's plans into disarray.

The Courier survived, however, and began a journey to the New Vegas Strip to find Benny and get revenge, in the process of learning the true purpose of the platinum chip and its power. The Courier was faced with the choice of either giving the chip to House or destroying the securitron army or even using it to create an army of their own. The Courier's journey attracted the attention of the NCR and the Legion, both wanting such an influential individual on their side. Also in preparation, the Courier traveled the land looking for other tribes and factions to ally with.

Hoover Dam
The Courier's role in the battle depended greatly on which faction they sided with. If the Courier sided with House or Yes Man, the battle played out in a similar fashion, both involving the activation of the securitron army. From there, the Courier was forced to fight their way across the dam and into the Legion camp. The NCR questline had the Courier perform the same basic task: fighting through enemy forces to get to the Legion camp on the other side of the dam.

While traversing the dam, any aid the Courier had enlisted would have been acted upon by the corresponding faction. Once the Courier reached the other side of the dam and entered the Legate's camp, they would face off against Legate Lanius. The resulting confrontation would either have had the Courier fight and kill the Legate, or solve the confrontation diplomatically. After dealing with the Legate, the Courier returned to the main gate, at which point General Lee Oliver and his men destroyed it. If siding with the NCR, Oliver would have congratulated the Courier; however, if siding with Yes Man or Mr. House, the Courier would have been forced to confront General Oliver, either fighting and killing Oliver and his men or solving the issue through diplomacy.

If the Courier sided with the polar opposite, the Legion, the battle played out in a similar fashion to the battle involving the Courier siding with the NCR, only it would play out in reverse; the Courier started at the Legate's camp, and then fought their way across the dam to reach the NCR's position, confronting General Oliver. Once again, the Courier was forced to choose between killing the General or convincing him to leave through diplomacy.

Elsewhere
The details of the battle at Hoover Dam are unclear, however, the fighting was not just limited to that relatively small location; violence engulfed the entire Mojave Wasteland as Caesar's Legion and its allies attacked NCR targets and locations across the region, with varying levels of success:
 * The NCR Embassy on the New Vegas Strip was potentially bombed, and if they had not been stopped by the Courier already, the Omertas attempted a coup d'état with a small army they had assembled but were stopped by the Chairmen and the White Glove Society, as well as the securitrons. If the Omertas were already dealt with, there was no attack. (NCR Emergency Radio)
 * Rioting broke out in Freeside, although its severity is unclear; if the Courier forged an alliance between The Kings and the NCR, the riots were far tamer. (ending slides)
 * The Fiends, in the event one or more of their leaders remained alive, attacked Camp McCarran. If the Courier eliminated all targets in Three-Card Bounty along with Motor-Runner beforehand, the Fiends were not able to mobilize and therefore the attack never happened, following Hoover Dam the remaining Fiends were easily hunted down. If the Courier killed at least one to three of the targets in Three-Card Bounty as well as Motor-Runner, the Fiends staged a poorly planned attack, only inflicting minor casualties upon the NCR. In the previously mentioned outcome, the Fiends were overall crushed, with the remnants being hunted to extinction by either the NCR or Mr. House's securitrons following the battle. If Motor-Runner remained alive, and at least one of the targets in Three-Card bounty was not eliminated, the Fiends led a brutal attack on Camp McCarran, inflicting heavy casualties on the NCR. In the event the NCR lost the fight at the dam and the Fiends were able to stage a large attack on McCarran the Fiends overran the camp, on the other hand, if the NCR won at Hoover Dam they were able to repulse the attack, but still with heavy casualties. If any of the Fiend leaders were alive and the Courier aided the Legion, the Fiends attacked McCarran but suffered heavy losses themselves, Caesar had their remaining number exterminated due to their poor performance. In the event that the Courier assisted Yes Man at Hoover Dam and the Fiends were able to stage an attack on the retreating NCR forces at McCarran, successfully overran the camp. In the years that followed the size of the threat the Fiends pose depends on their remaining leadership, varying from a minor nuisance to a prevalent power in Outer Vegas. ending slides
 * Camp Forlorn Hope was attacked by the Legion. If the Courier did nothing for either side, the Legion was able to take it with some difficulty, with some NCR troops managing to retreat. If Alpha Squad of 1st Recon was present or the Courier managed to solve the camp's many problems, the NCR soldiers were able to defeat the attack with very few casualties. If the Courier aided the Legion, the camp was totally overrun. If the Courier solved the camp's problems and Alpha Squad of 1st Recon was present, then the engagement was such a crushingly one-sided NCR victory that an officer says it will "surely be the most decisive victory in this entire battle." (NCR Emergency Radio)
 * The Legion's frumentarii made an attempt to bomb the monorail outside McCarran, whether it was successful or not depends on whether the Courier previously uncovered their plot. (NCR Emergency Radio)
 * Camp Golf was attacked by the Legion. If the Courier did nothing for either side, the NCR Rangers defeated the Legion, throwing back their attack with moderate casualties. If the Courier trained the Misfits, the Legion was defeated more easily, with the Misfits distinguishing themselves. If the Courier aided the Legion, then the camp fell and Chief Hanlon and the other rangers stationed there were killed, many by crucifixion. (NCR Emergency Radio and ending slides)
 * Novac was attacked by the Legion. If the Courier did nothing, the townspeople fended off the Legion, but many of Novac's citizens died in its defense, leaving it vulnerable in the following days when it was ravaged by Feral Ghouls. If instead, the Courier aided the Bright Brotherhood in starting their pilgrimage, they returned to help the citizens restore the town following the attack, allowing Novac to survive. If the Courier aided the Legion, the civilian population was eventually massacred following persistent Legion attacks. (NCR Emergency Radio and ending slides)
 * If Yes Man was told to ignore or Caesar was convinced to temporarily spare them without making peace with the NCR, the Brotherhood of Steel would have attacked and taken over HELIOS One. They then would have inflicted casualties on the NCR troops fleeing from the Mojave. If they were convinced to sign a treaty with the NCR beforehand, the Brotherhood instead aided the NCR during the battle at Hoover Dam by sending power-armored Paladins to fight the Legion. If they were wiped out prior, the Brotherhood played no role. (ending slides)

Appearances
The Second Battle of Hoover Dam occurs in Fallout: New Vegas.