The story begins when Chico Mangano dies by a gunshot. There were witnesses who saw Chico's three brothers kill him.
Their uncle phoned up their grandad and he said that he saw the trio somewhere where he lived. So the grandad sent the 5th grandson called Mario to avenge Chico's death and you are Mario the main character.
Gameplay may be described as a a cross between The Sims and Grand Theft Auto. You have to build an empire and start businesses and basically you have to build up a gang.