The game begins not a long time after Duke Nukem 3D. Duke is relaxing in Bootylicious with a few beers and some babes when suddenly Pig Cops start trashing the place and turn his 1968 custom hog into a chopper bike. Duke trashes all the Pig Cops and then finds out that the aliens are trying to get to the past in order to take over the world before Duke was there to stop them.