Neverwinter Nights 2 (also known as NWN2) is a computer role-playing game developed by Obsidian Entertainment and published by Atari. It is the sequel to BioWare's Neverwinter Nights, based on the Dungeons & Dragons pencil and paper fantasy role-playing game. Neverwinter Nights 2 utilizes an adaptation of the Dungeons & Dragons 3.5 edition rules.
Players create player characters to represent them during the game, using the same character creation rules as found in the Dungeons & Dragons game. They may gain the assistance of up to four or more additional party members, and they eventually acquire a keep that can be used as a base of operations. Neverwinter Nights 2 is set in the Forgotten Realms campaign setting - in and around the city of Neverwinter. The story is mostly unrelated to Neverwinter Nights and follows the journey of an orphaned adventurer investigating a group of mysterious artifacts known as "silver shards" and their connection to an ancient, evil spirit known as the King of Shadows.
Source: Wikipedia, "Neverwinter Nights 2," available under the CC-BY-SA License.