A tough space marine (Imprisoned for disobeying orders and assaulting his commanding officer) along with his squadron are sent to a radioactive waste facility on the planet Mars. The facility owned by UAC (Union Aerospace Corporation) which has been infested with fierce alien creatures from hell that have arrived on Mars due to a experiment involving "Inter-Dimensional Gateways" portals that allow people to travel from part of the galaxy to another. When his squadron are killed off one-by-one by the creatures. The space marine who is the only marine in the squadron left alive, finds he cannot get off Mars, arms himself with a arsenal of weaponry (Pistol, Plasma Rifle, Shotgun, Chainsaw) engages in a non-stop battle, as he fights the alien creatures, marines gone bad and armies of monsters, and fight for survival as he sets out to prevent the alien creatures and their army of marines gone bad and monsters from reaching Earth, where the human race will end up meeting it's doom.