MR. D is a killer. A cold, calculating, brutal gun for hire. A rising star in the Mafia, he is sent from his home in New York to the suburban home of Chris and Genie Richardson, to take care of some urgent business. Unfortunately, the mark isn't home and Genie Richardson is left all alone with Mr. D and his gun.

Space pirates, led by diabolical Colonel Fraser, take over a cargo ship carrying anti-matter explosive and an important official. Space marines, led by Captain Gray, must stop their evil plans.