- "Things aren't gonna work out quite that way. There's a bit of a problem..."
- ― Dave Norton.
- "That's right, Davey boy! You could say that!"
- ― Steve Haines, interrupting right before his betrayal.
The mission starts with Michael approaching Dave Norton at one of the lookout points in Kortz Center. Michael confirms that the raid at the FIB's headquarters was succesful and insists upon Dave and Haines' promise to let him and his friends go after that final job. Norton begins to explain that there's been a change of plans, but he is promptly interrupted by the arrival of Steve Haines, who proceeds to betray the two by telling Andreas Sanchez to arrest them. A four-way Mexican standoff is initiated by the men, but they are quickly talked down by Norton. Before they can lower their guns, however, a group of IAA agents (led by the U.L. Paper Contact) arrive and attempt to arrest all four of them. They are soon joined by a rival group of corrupt FIB agents (who were contacted by a treacherous Sanchez) and a platoon of mercenaries from Merryweather Security. Haines gets shot in the leg by an FIB agent and then he shoots Sanchez in the head, sparking a massive shootout between all those involved.
At this point, the player regains control and the mission starts proper. Haines escapes and Norton gets separated from the player after a helicopter crashes into a walkway and destroys it. The members of the rival agencies will be shooting at each other and will kill each other gradually, simplifying the task of eliminating them.
Another Merryweather helicopter will arrive and corner Michael. The game then switches the player over to Trevor, who is on a nearby ledge with a sniper rifle. Trevor must then take out the helicopter pilot to let Michael pass through the walkway. After Trevor makes his presence known to Michael and Dave in a brief cutscene, the player must use Trevor and his sniper rifle to clear out the enemy FIB agents from the courtyard to let Norton get across it.
Now the player can choose to continue as either Trevor or Michael. If continued as Trevor, the player has to help Michael get down to the courtyard, clearing out FIB agents and another Merryweather helicopter from a distance. If switched over to Michael, the player must make their way down to the courtyard, shooting their way through the FIB agents (Trevor, controlled by the game's AI, will take care of the Merryweather helicopter).
Once Michael is next to Dave in the courtyard, Merryweather agents will start to arrive and attack all three of them. Using either Trevor or Michael (or alternating between them), the player must take out all the incoming Merryweather agents and another one of their helicopters. Once these agents are taken care of, Trevor will leave and the player must continue the rest of the mission as Michael. The player must make his way to the parking lot with Dave and clear out the Merryweather agents waiting there. Once all the agents are dead, Dave will get into his car and will tell Michael to call him once the heat has died down, before driving away.
The player must get into one of the cars in the lot and drive away. As the player leaves Kortz Center, a final Merryweather helicopter will begin attacking Michael. The player can either try to lose the helicopter or get out of the car and take it down. Once the chopper is dealt with, the player will recieve a call from Trevor, saying to meet him in Morningwood. Once there, a cutscene will play where Michael and Trevor discuss Trevor's return and their planned "last big score" at the Union Depository. Once the cutscene ends, the mission is over.
- Andreas Sanchez - Killed by Steve for working with a rival agency and telling them Steve's illegal activities.
- United Liberty Paper contact - Can be killed by Michael, FIB agents or Merryweather agents.
- FIB and Merryweather agents - Killed during the shootout.