The protagonist of the game, Nick Vrenna, has been unjustly incarcerated in a prison where the staff are performing unethical medical experiments upon the inmates. A prison riot occurs and an experiment goes horribly wrong. The people inside the prison - except for Nick, who seems to be immune - get infected with a substance called Abuse that transforms them into monsters. Nick takes a laser gun and goes on to single-handily destroy all mutants, stop the substance from spreading further, and escape from the prison complex.