Cadillacs and Dinosaurs: The Second Cataclysm

You find yourself in the so-called Xenozoic Age - after a cataclysm in 2020 A.D., mankind was forced to hide beneath the surface. Once it could come out again, it found the world terribly changed, with dinosaurs roaming freely once again. A mysterious mutant-like race, called the Grith, believe the cataclysm was caused by the upsetting of the natural balance. Now, the leader of the restored City in the Sea, Scharnhorst, is using old technology and disrupting the balance again.