Walkthrough for A Civilized Man of Red Dead Redemption: Undead Nightmare.
1. Go to Las Hermanas marked with M on right of the Perdido to meet Mother Superior.
2. Go to R mark in left side of the map to meet Reyes at the Escalera.
3. Shoot Reyes and tehn
4. Enter the catacombs marked with Yellow Dot.
5. Go through the broken wall.
6. Middle entrance is your main path but there is a new weapon on left one.
7. Remember that you need to kill every zombie appearing as Red Dot in your path.
8. Reaching the dead end in a more open room with columns, a cutscene will trigger.
9. After killing around ten zombies, go to the girl.