Most of this story probably follows the original story of Farcry 3. But just has many of the GTA characters fill the roles. Along with a few other chances as well, so that it's not just a complete REWRITE of the game..
The story starts off by re-showing FARCRY THE EXPERIENCE.
Christopher Mintz-Plasse is filming a show on survival on Rook island. He keeps trying to make an introduction to the show, but continuing to screw up his lines, while also annoyed that his superiors and the rest of the crew is on a ship of the coast of the island partying while Chris and his camera-man, Barry are stuck making the survival show. They spend the next few hours adventuring through the jungle trying to find fresh water and continue to bicker and mess with each other. Eventually, they find fresh water and stop so Berry can film Chris drinking. While in the middle of his "acting thirsty," Chris fails to notice a dead monkey bleeding into the stream he is drinking from. He runs off to vomit and warns Berry that he better not put it on the internet. Just at that moment, they hear a hunting trumpet and someone yelling, "Bambie", into the jungle. They go to investigate and while in a clearing, come across a man with his body in the middle of a deer. The man begs them not to kill him. Just as they say that they aren't going to kill him, gun shots are fired and the man runs in one direction while Chris and Barry run for some bushes near by, just as, "BAMBIE!" is heard again. Now, closer then ever.
Chris and Barry are hiding in the bushes beside the clearing as they watch Vaas Monologue and two of his men enter the clearing. The two holding assault rifles and Vaas riding on the back of another human like a horse. Vaas claims his "horsie" needs a break and gets off his steed. He then proceeds to shoot the man through the head, claiming he was a better horse than he ever was a man. Vaas then spots something and starts walking towards Chris and Barry's hiding spot, claiming he smells something. Before he can get any close, the cries of the man inside the deer are heard again, and Vaas and his men head off to find him. Chris and Berry crawl out of the bushes and try to make a call to their boat to get picked up from the island. The passengers, thinking he is bluffing, don't take him seriously. The passengers then spot more pirates on the beach and, thinking they are other "party peeps", cheer and wave before the pirates shoot at them, eventually destroying the boat. Chris and Barry then see black smoke coming from some where in the distance and run to investigate. The smoke is coming from the remains of the destroyed boat and they find bloody corpses on the beach that Berry thinks is the captain. Before they get any closer, gun shots are heard from a few hundred yards away along the beach and Vaas screaming, "IMPERIALIST, COLONIALIST, FUCKS!"
Barry and Chris are now hiding behind a patch of rocks while witnessing the capture of a few survivors of the cruise ship. One of Vaas's man brings him one of the cameras that was on the boat and begins to record what is going on. Vaas then brings forward a girl named Jennifer and two other men which were Chris' agents. Vaas pulls out his gun and forces her to choose which one deserve live and which one deserve to die. The men then begin to fight with each other over who is the more deserving of death and Vaas forces Jennifer to shoot both of them, before sends her away to the camp. Vaas's man brings over an iPad, showing the introduction of Chris's survival show. Knowing that Christopher is on the island, Vaas becomes excited and tells his men that "McLovin" is here on the island. He pulls out a walkie-talkie and makes contact with Chris. While Chris pokes his head out from behind the rocks, Vaas spots him and Chris and Barry are forced to run from Vaas's men. Vaas then says to his camera man that they are going to make a reality show of them chasing Chris and then proceed to chase after Chris as well.
Chris and Barry continue to run from Vaas' pirates while Barry is still recording. Barry then twists his ankle and falls down. Chris is quick to abandon him just as a pirate shows up a points his gun at Barry. Just before he can kill Barry, Chris returns and slices the head of the pirate, picks up his AK-47 and shooting several more pirates before running off into the jungle. After running for a bit, they find themselves in the pirates' camp with bodies of men and women buried up to there necks in the dirt.
One body, however is still alive and tries to bite Berry's leg. Barry is then shot in the leg and falls. Chris says he is not gonna leave him but he tells Chris to abandon him. Chris runs just as Vaas shows up and head-butts Barry into unconsciousness and picks up the camera, telling anyone watching not to vacation there and turning off the camera. After an unknown amount of time, the camera is turned back on, showing the torture of Barry and Jennifer. One of Vaas' pirates films Vaas trying to talk to Chris on the walkie-talkie, telling him if he doesn't meet Vaas, he will cut Barry into little pieces. Barry tries to tell Chris to run, but Vaas shoots his already injured leg. Fed up from Barry's screaming and crying, Vaas yells at him to shut up or he will kill him. All of sudden, Chris shows up trying to rescue Barry. Chris and Vaas then get into an argument over who should put their gun down. All the pirates in the compound point their guns at Chris, in which he threatens to shoot all of them if Vaas comes any closer. Vaas takes one step and Chris fires all his rounds but somehow does not manage to hit a single pirate. Vaas asks if Chris has any idea how rude that was. Chris, realizing his mistake, makes a run for it and the pirates chase after him.
After an unknown amount of time Vaas shows that he did indeed capture Chris and buried him up to his neck in sand. And spends the next few days torturing Chris for his own amusement. Even going as far as feeding Chris parts of Barry's now blown up body.
A few days later, Vaas notices that Chris is not responding; he thinks Chris is pulling a trick he pulled three times before, but checks his pulse and realizes he is dead. He makes two attempts at mouth-to-mouth resuscitation before bowing his head in silence. Then another pirate runs up with news; Vaas yells at him for disturbing him before the pirate tells him six more people have landed on the island. Much to Vaas's excitement at the opportunity of having more people to torture.