This is a Gravina Crime Family mission.
"You got the low-down on Frankie Stones. He's a high-up mobster from out of town who is here to discuss the end of a long-running turf war. That asswipe Gravina's going to have a lot of explaining to do to the Commission when Stones shows up dead..."
This mission involves a pretty good sized firefight against numerous gangsters, so you will want to be in full health and stocked up on plenty of ammo, including grenades, before you start.
From the mission start, get in your car and drive through the chain link gate and down the dirt road until you reach the Old Observatory. Drive your vehicle around and park on the north side; you'll need it for cover momentarily. Get out and when you reach the map marker you'll find out you've walked into a trap. Pull out your weapon and using your car as cover, start taking out the ten or so gangsters who will come in from the east.
As you make your way back towards the road a few more will spawn further east and several more will be taking cover behind some vehicles down the road. Work your way back the way you came in, using the vehicles as cover. As you proceed forward most of the gangsters will be standing behind vehicles for cover. To take them out quickly remember to shoot the gas tanks on the vehicles or throw a grenade to blow them up.
As you approach the the bend in the road you will want to get in a vehicle, as the next group has made a roadblock further down and there is no cover whatsoever between you and them. Drive until they're within grenade throwing distance and then get out and take cover next to your car. These guys can be hard to get a clear shot at because they tend to stick tightly in their cover so your best bet is to blow up the cars by tossing grenades at them.
Once you've killed the last group you're all set. Just head back down the road and when you reach the map marker at the gate you will immediately be told to get to the safe zone. Head there to end the mission.
- This mission is the only time you can get the Shubert 38 in this DLC. You should see them parked along the road as you go through this mission. If you want one, you need to take it before you head for the safe zone as they will disappear once you activate it.
- It's possible not to kill any of the gangsters in this mission by bringing along a fast heavy vehicle like a Houston Wasp or a Walker Rocket. Then when you get the message that it's a trap, just drive out and smash through the roadblocks as you go. When you get to the end of the dirt road it will tell you to go to the safe zone and end the mission.