 Like other games in the Neverwinter Nights series, Mask of the Betrayer takes place in the Forgotten Realms campaign setting. The story is a direct sequel to the plot of Neverwinter Nights 2, set almost immediately following the events at the main game's end. The main campaign is set in Rashemen near the kingdom of Thay, and the Red Wizards of Thay are a driving force behind the campaign story.
