Red Dead Redemption Undead Nightmare

Plot

Shortly after completing his mission to hunt down the surviving members of his former gang for the Bureau of Investigation, John Marston is living a peaceful life with his family and friend Uncle at Beecher's Hope. One night however, a storm is raging and Uncle has not returned. After John and his family go to sleep, Uncle comes back zombified and bites Abigail, who then bites Jack. After killing Uncle and tying up the infected Abigail and Jack, John sets out to find a cure. Arriving in Blackwater to look for a doctor, he finds it mostly abandoned and runs into one of his allies from the game's main storyline, Professor Harold MacDougal, who has returned from Yale and expresses suspicion that a virus has caused the dead to come back to life. MacDougal is then killed by an undead Nastas, another one of John's allies who had been killed. After clearing Blackwater of zombies, John discovers that there are three possible causes of the plague: the Mexicans, con artist Nigel West Dickens, and treasure hunter Seth Briars, both allies of John as well. John talks to both men and learns neither of them know what caused the outbreak, though he agrees to help them with a few favours, while also aiding other survivors, including previous allies of his, such as Marshal Leigh Johnson, rancher Bonnie MacFarlane, and elderly gunslinger Landon Ricketts.

Eventually, Seth voices his suspicions that the Aztecs had something to do with the plague, prompting John to travel to the Mexican state of Nuevo Paraiso, upon obtaining an army uniform so that he could pass the border, at Nigel's advice. John finds that Mexico is in a much worse state than America, and encounters a group of nuns led by Mother Superior Calderon. After helping them clear their town and cemetery of zombies using holy water, facing an undead Captain Vincente de Santa in the process, John is told by Calderon that she learned from a woman that former rebel leader Abraham Reyes, whom John previously helped take over Nuevo Paraiso, is responsible for the plague. Upon meeting said woman and killing an undead Reyes, John learns that Reyes triggered the zombie plague when he stole an Aztec mask from some tombs, which transformed him into a zombie as well when he put it on his face. Venturing into the tombs, John and the woman are able to return the mask to its original place, effectively stopping the plague. The woman then reveals herself as the Aztec goddess Ayauhteotl and thanks John for his help, offering him one of the four horses of Apocalypse to return home.

John returns to Beecher's Hope to find that Jack and Abigail have been cured, and is happy to be reunited with them. Months later, following John's death in the main story, Seth finds and steals the mask, once again unleashing the dead. As a result, John rises from his grave. However, having been buried with holy water, he becomes a revenant, and keeps possession of his soul.