It's a simple mission where you have to do the same thing as before in Big Smoke's Crack Palace: kill vagos, ballas, rifa, russian mafia. But on the last floor instead of having that fat fool of Smoke, another well known villain will ty to kill you and the SWAT will protect the villain.
I recommend new weapons mod and effect overdose (explosions, fire, bullets more realistic) installed in your game so it's more fun to do this mission.