Duke Nukem Forever is a first-person shooter video game for Microsoft Windows, OS X, PlayStation 3, and Xbox 360. It is a sequel to the 1996 game Duke Nukem 3D as part of the long-running Duke Nukem video game series. It started development at 3D Realms and Triptych Games, and was finished by Gearbox Software and Piranha Games. The game stars the titular action hero who must come out of retirement and save the world from aliens when they begin kidnapping the women of Earth.