Fallout: New Vegas takes place during the year 2280, three years after the events of Fallout 3, and 203 years after the Great War of 2077, making this installment chronologically the latest in the series thus far. The game is set in post-apocalyptic Las Vegas, Nevada and the Mojave Desert. Landmarks featured in Fallout: New Vegas include the Hoover Dam that supplies power to the city and the Helios 1 solar energy plant. Unlike other cities in the Fallout series, Las Vegas was not struck directly by a nuclear attack. Its buildings remain intact, and mutation of its inhabitants is minimal.
The game places the player in the role of a courier, found in a shallow grave after being shot in the head and left for dead by the leader of a crime family. The Courier is rescued by a robot who brings him to a doctor. After treating the courier's injuries, the player enters into character creation (defining skills and attributes, name, gender, age and appearance) and begins investigating the assassination attempt and recovering the stolen package, as well as exploring the post-apocalyptic world.
Various in-game equipment kits are available as pre-order bonuses: Depending on which retailer the player purchases through, the style of armor and additional gear granted will be different.
Source: Wikipedia, "Fallout: New Vegas", available under the CC-BY-SA License.