Fallout New Vegas Eureka!

The optional objective is of no consequence, just gun through the Hoover Dam powerplant until you can exit through the Hoover Dam Visitor Center. Move northward across the Dam, killing Legion members along the way. You will get a breather in a tented section through a wooden door. If you have a detonator and 100 science, you can hack a terminal and connect it with the detonator, which will allow you to blow some generators and kill the next squad of Legionaries instantaneously. Keep fighting until you reach the Legate's Camp. Kill the defending Legionaries. You now have two options: you can (try) to kill the Legate, or you can use 90 speech and 100 barter to make him retreat the Legion from battle. Killing him is tricky since he's fast, has a lot of HP, and is a hard hitter. It is possible for him to two-hit kill a player if you're not careful. If you want to make him surrender with 90 speech rather than 100 speech, you will need to bluff and lie to make him back off. After he retreats or is dead, try to exit the camp to face a triumphant General Oliver. Finish speaking and watch the ending slideshow!