Mysteries of Westgate is a single-player role-playing adventure developed by Ossian Studios and released in 2009 for Windows as the first Adventure Pack for Neverwinter Nights 2. Set in Westgate, a corrupt port city on the Forgotten Realms' Dragon Coast, the expansion tasks players with uncovering the secrets of an underworld ruled by a criminal organization known as the Night Masks. Characters begin at level 8 and can progress to level 14 across four distinct city districts — Harbor Loop, Market Triangle, Arena District, and the subterranean Undergate — in an adventure offering over 15 hours of non-linear gameplay. Multiple paths and endings, alongside an influence system that shapes the fates of three recruitable companions, give player choices meaningful consequences. The pack also introduces new creatures, tilesets, music, and voice acting. It requires the base Neverwinter Nights 2 game and is compatible with the Mask of the Betrayer and Storm of Zehir expansions, though neither is required.