Duke Nukem returns to Los Angeles in an alien vessel (on extended loan), expecting a hero's welcome. After all, he defeated the Rigelatins and blew up their ship. Before that he single-handedly saved humanity from the clitches of Dr Proton and his assassin automatons (oooh, they were evil). But, no, instead Duke is nearly blown out of the sky. Barely able to eject, and precisely at the right moment, Duke miraculously saves himself by landing on a skyscraper rooftop (convenience comes naturally to Duke). Suddenly, Duke realizes that L.A. is under siege. A swarm of alien races landed while he was gone and took over. Their intentions aren't clear, but one thing is for sure - all over the city there are hundreds of helpless human females encased in green, slimy cocoons who don't look particularly happy. Welcome back to Earth, Duke. He's here just in time to save humanity (again) and find out what the aliens want with our women.