Walkthrough for Get Back in That Hole, Partner of Red Dead Redemption: Undead Nightmare.
1. Travel to right side of the Map marked with U to meet Seth Between Thieves' Landing and MacFarlane's Ranch.
2. After talking with Seth, three green skills will appear on the New Austin. Go to each one of them and clean them off of any zombies.
3. Graveyards marked with green skull in the Map are Coot's Chapel near Armadillo, Odd Fellow's Rest near the Ridgewood Farm, and the Church in the abandoned town of Tumbleweed.
4. Save as the first graveyard, you need to burn all the Coffins and kill every zombie you see.
Tip: If you are having a hard time killing zombies in the graveyards, run them next to the burning Coffins and they catch fire and burn to to death.
5. After clearing all three graveyards, get back to Seth marked with S in the right side of the Map.