“Okay, your gunman can provide you with options on where to steal untraceable weapons. These guns will not lead back to us if the shit hits the fan. And I know you're a genius, okay, but I've seen a lot of shit hit a lot of fans in my day.”
Once an approach has been chosen for the heist, the player has to choose a gunman. Each gunman has two options for the weapon loadout, and once chosen, the mission will begin. The player will be given one of the possible types of the mission. Some of the mission types require two sets of weapons to be stolen and delivered, so at least two players are recommended.
“Let's go shopping for some weapons, eh? Some that won't trace back to us. Your gunman has a line... but you might not like it... Oh hell, it's a cache at a Lost MC clubhouse. You've gotta assault their base, fight your way past the bikers, find the guns and bring 'em home. Ooh, I'm out of breath just saying it.”
— Lester's briefing for the Lost MC variant.
“Hey, uh, so those weapons, yeah? The ones that won't trace back to us? It looks like the best option is a cache the Vagos are holding at their Los Santos HQ. I know, I know, kinda... inconvenient, but you could just roll up there, fight your way in, and bring the guns back to the base and we'd be set. It's easy right? Cool...”
— Lester's briefing for the Vagos variant.
The player is tasked with going to either a Lost MC clubhouse in Paleto Bay or a Vagos clubhouse in La Mesa. Except for the location and gang, the two mission variants play out the same way.
Once there, the player needs to first kill the bikers outside and then enter the clubhouse. Inside, they need to take care of the enemies and steal two duffel bags of unmarked weapons. If playing solo, the player needs to return to the building twice, as only one bag can be carried at once.
When the weapons are delivered to the Arcade, the mission is completed.
“Got 'em? Okay, now bring 'em in. Not the goons, just the weapons, please.”
— After collecting a bag of unmarked weapons.
“Okay. Untraceable weapons. Or, uh... at least ones that won't trace to us. Your gunman found what we need on a Merryweather flight manifest, but we can't locate the plane. So, you'll have to procure a flight schedule from a mercenary compound. Sound fun?”
Once the players nears the plane, they need to blow open the rear door of the plane, after which two crates of unmarked weapons will fly out. The player has to collect them and bring them to the Arcade, after which the mission will end.
“Good. You're there. One of those goons must have the schedule on him, so, how about... taking 'em all out and seeing who drops it. Cool? Great. Good. Thank you.”
— After arriving at the Naval Port.
“You got it, give me a second to track the right plane. There we are, your bogey is now on radar. Get up there and after it by any means.”
— After collecting the flight schedule.
“Okay, it's like a piñata, break the ramp door open and the goodies will come pouring out. Then grab the stuff and bring it in.”
— When nearing the Titan.
“Now, bring me those weapons, come on!”
— After the rear door of the plane is opened.
“Your gunman has a plan to get you weapons... it's not gonna be easy, but... at least they can't be traced back to us. So, you know who's got weapons when budgets are shrinking for everyone else? The military. They're loaded on a vehicle in Fort Zancudo. Give it your best shot.”
— Lester's briefing.
The player is required to go to the munitions depot in Fort Zancudo. The unmarked weapons that need to be stolen are loaded into a Barrage ATV. Many soldier can be seen doing various activities near the vehicle, such as doing push-ups and shooting targets. They will become hostile towards the player as soon as they near the depot.
After the enemies are dealt with, the player has to steal the Barrage and evade a four-star wanted level. Once they have done so, the vehicle needs to be deliver to the Arcade, after which the mission ends.
“How's that for an arms deal? Bring 'em in! But you gotta drop your tail first. I don't wanna end up on a general's kill list.”
— After collecting the weapons.
“You want some weapons that won't lead back to ya? I got you some weapons that won't lead back to ya. NOOSE found them on a raid on some doomsday preppers. I'm sending you live locations for all the NOOSE vans in the field, you gotta find 'em, identify the one with the weapons in it, and bring the guns back here.”
— Lester's briefing.
The player will be sent four locations of NOOSE vans around the map. They need to travel to them and blow off the rear doors to inspect the contents.
Once the van carrying the unmarked weapons is found, it needs to be stolen. After evading the three-star wanted level, the van needs to be delivered to the Arcade to end the mission.
“Bingo... bring it home.”
— After finding the correct van.
“That some arsenal or what? Bring it in. And I shouldn't have to say, but don't bring any cops with ya! This heat really isn't gonna help.”
— After getting in the van.
“We've traced some untraceable weapons for ya. If you're quick, you can head over there and grab them before they're seized by the cops.”
— Lester's briefing.
The player has to travel to Stoner Cement Works to acquire some unmarked weapons before the police seizes them. While travelling to there, Lester informs the protagonist that the police has already arrived there, but that they can still attempt to get the weapons.
The player has to manoeuvre their way around the police patrols and collect two sets of unmarked weapons. If a police officer spots them, they will need to evade a 3-star wanted level before delivering the cargo. Once all unmarked weapons are brought to the Arcade, the mission ends.
“Shit... looks like the cops got there already... they're swarming all over the place. We might be okay though, just... keep going and we'll take a second look at the situation when you arrive.”
— While travelling to the destination.
“Okay, okay. Not too bad. Cops are thin on the ground... must be a sale at the donut shop, huh. If you play this smart, you might be able to get in and out with the shipment without them suspecting a thing.”
— After arriving at Stoner Cement Works.
“Well, that didn't go to plan. Lose the heat before ya bring those weapons back here.”
— If the police is alerted.
“Right, so your weapons. We don't want anything that can be traced back to us, so we're going after a little import export operation off the coast. Blast in there and take the shipment. I'm sure we could pull this off with any old thing from Ammu-Nation, but... we gotta be careful. I mean, I appreciate irony as much as the next lazy gen-exer, but I didn't come out of retirement just to be put in a jail cell. And... we have Georgina to think about... so... um... you know...”
— Lester's briefing.
The player is tasked with going to Palomino Highlands, where they need to search the coast for a group of smugglers. Once located, they have to be killed, which will reveal the location of the unmarked weapons. They are located in a Tula just off the coast from the smugglers.
The player needs to steal the plane and deliver it to the Sandy Shores Airfield to end the mission. Enemies will give chase until the Tula is delivered; while the mission can be done solo, an extra gunman can help by taking out the pursuing helicopters.
“We must be a little late to the party. You should go ask 'em nicely where they stashed the guns.”
— After locating the smugglers.
“Easy does it... give yourself a good run and takeoff. Then I'll need you to land at the airfield I've marked on your GPS. Your gunman'll be there to collect the shipment.”
— After getting in the Tula.
“Take her down gently... don't wanna wreck the shipment and yourself. Oh, a-and make sure the wheels are down... seems obvious I know, but...”
— When nearing the airfield.
After the mission is completed, Lester tells the player where the weapons will be stashed.
“Your gunman will stash the unmarked weapons at the casino for ya. They'll likely be dropped into the laundry room or waste disposal. You might wanna remember this on the heist, otherwise you'll be down to just a pistol.”
GTA Online The Diamond Casino Heist - Heist Prep Unmarked Weapons Solo (Clubhouse)