Grand Theft Auto: San Andreas Walkthrough

CJ and Sweet are still at odds when Cesar shows up with news that his hood is under attack. He needs help to push out the yay-slinging punks.

Recruit a couple Grove Street gang members to join your gang, then hop in a car with Cesar and head over to Unity Station, marked by a yellow blip on your radar.
With the team all together, it's time to head into the barrio. Take out all the enemies infesting the area, as they're marked with red blips on your radar and over your head.
Take out each of them, with many hiding behind corners and sneaking up behind you. Use your gang members as allies don't run too far ahead of them.
Once you've taken them all out in the barrio, head to the alleyway, marked by a yellow blip on your radar.
Now in the alley, it's time to take out more of the rival gang. Continue to shoot at them from down the alley. Stay ducked and roll behind the car as necessary when reloading.
Make sure to watch your sides, as your enemies will attempt to flank you from the side streets.
Kill the group of enemies that hop over the fence behind you. If you need additional health, keep your eye open for open car ports leading from the alley.
With the alley clear, take out the gang members at the corner house. Target the guy on the roof first, as he has he'll be firing an RPG toward you. Your 2nd target should be on the left-hand side. You'll spot him as the one with the flamethrower.
Once all the enemies are dead, you've passed the mission.