Find Collar 12: Christine

 is a quest in the Fallout: New Vegas add-on Dead Money.

Overview
This quest is given to you by Father Elijah after completing the quest Sierra Madre Grand Opening! He instructs the Courier to recruit three companions in order to perform a heist against the Sierra Madre Casino.

Quick walkthrough

 * 1) Find the Medical District.
 * 2) Enter the Villa Clinic.
 * 3) Enter the Clinic Basement by using the key, which is located in a desk on the second floor.
 * 4) Turn off the Shielded Speakers by using the terminal in the Clinic Basement.
 * 5) Find Christine in the malfunctioning chamber, recruit her to your group.

Detailed walkthrough
Enter the Villa Clinic, either through the upper floor or through the main entrance at street level. It is advisable to set the hologram to patrol the floor the player is not on. On the second floor hallway, by one door, is the computer to set the patrol parameters for the hologram. Set this to first floor (ground), then go to the emitter, which is near the center of the main second floor corridor. (It looks like a lit blue plasma mine). This can be disabled with a Repair check, or the hologram can simply be avoided. When Elijah tells the player to find a way to disable the speakers in the Auto-Doc hallway, move to the basement, the door of which can be unlocked with a lockpick check or a key found on the second floor in a desk (Along with the Med-X dispenser code.). From there the player needs simply to shut down the main power and go back upstairs, go down the Auto-Doc hallway, and activate the Auto-Doc in the last room of the hallway. This frees Christine, who will join the Courier if he/she doesn't have another follower at that time.

The best solution to this quests seems to be taking a very cautious approach, saving regularly and avoiding conflict at all costs. At certain points you will just have to run past an enemy.

Gallery
Fallout: New Vegas quests