IntroductionCatalina has double crossed you again, but this time you'll make her pay. You need to escape the Cartel mansion.
I Will Have My VengeanceGrab the pistol which has just been dropped by the guy you punched in the cutscene, then run to the open garage and grab the body armour. Get in the Cartel Cruiser and use it to run over any more Cartel who are alive. Grab their weapons, then head out of the gate. You'll see a cutscene where a helicopter will fly overhead towards the dam. Head to the right, and go across the bridge towards the police station. Head around behind and fill up your health and armour, as well as buying some flamethrower and molotov cocktail ammo. Head along the top of the dam, and then go down and around until you are at the entrance to the lower dam. Smash into the two Cartel Cruisers blocking the entrance and kill the two Cartel guards. Grab their AK-47's and proceed down the hill. To your right you'll find a Sniper Rifle which comes in useful for picking off the Cartel situated in the watch towers to the right. Move in towards the main entrance to the lower dam and ram the truck out of the way, trying to kill the people down there with your vehicle. If needs be, get out of your car and use your guns to kill the people on top of the crates. Shooting the red barrels is also a good way of disposing of enemies. Work your way along, killing everyone you see and eventually you'll see another cutscene where Catalina flies away in the helicopter. Move fast! She'll launch a barrage of rockets at the dam which will pretty much instantly kill you. Run like hell to the stairs leading up to the helipad and try to kill the other guards down there. As you go up the stairs you'll be attacked by a few more Cartel, one with a flamethrower so kill them quickly, but watch out for Maria, then run to the Rocket Launcher. Catalina will be in the air by now, but she will fly back towards you and launch rockets. Fire your Rocket at the helicopter and watch the explosion. Head back over towards Maria, and kill any remaining Cartel. Move close to Maria and you'll complete the mission and the game.
Additional NotesThat's all of the main story missions complete and the end of GTA3. If you're going for 100% you've still got a lot to do though, because this doesn't even account for half of the game!