The Nuka-Cola Challenge

 is a Fallout 3 quest connected with the Nuka-Cola soft drink. It is also an Xbox 360 and PC achievement.

To start this quest, find Sierra Petrovita at Girdershade, which is located west of Jocko's Pop and Gas Stop or SW of Smith Casey's Garage (You will go to the garage during a Main Quest).

Upon finding Sierra Petrovita, she offers you to take the "Nuka-Cola tour," which consists of viewing the large number of Nuka-Cola collectibles she owns. If you agree to take the tour, she will show the player around her home, discuss various Nuka-Cola facts and talk about some of the items in the room. After the tour, she gives the player an Ice Cold Nuka-Cola.

She then asks the player to collect Nuka-Cola Quantums and says she will pay 40 caps for each bottle. Once she has been given 30 bottles, enough to fill her Nuka-Cola Vending Machine, she provides a schematic for the Nuka-Grenade.

After exiting her house, Ronald Laren will ask the player to instead give him the Nuka-Cola Quantums, as he hopes that giving them to Sierra will improve his chances of having sex with her. He offers to pay the same price for the Quantums, though a successful Speech check will cause him to double the payment. You also have the option if you have the Black Widow perk to do a threesome in exchange for him finding the bottles.

The name of this quest is a reference to "The Pepsi Challenge," a taste-test marketing promotion run by PepsiCo since 1975.

Information in the Nuka-Cola Plant reveals there are three caches of Quantum, in Paradise Falls, Super-Duper Mart, and Old Olney. Each location has only about 5 bottles, so you'll have to find more on your own.

Bottle locations

 * Old Olney's supply is in a truck, east-southeast of the town. A red rocket is your landmark.
 * Paradise Falls's supply is under the stairs in Eulogy's pad.
 * Super Duper Mart's supply is in the market. There are a few in the back supply room with the Protectron.
 * The Nuka-Cola Plant itself will generate 3 bottles on the conveyor.

An external guide lists exact bottle locations. by MdsFinest

Single bottles can be found in many locations involved in other quests.
 * On top of the cage just inside the main entrance of Springvale School (Go around and up stairs to get on top of the cage. Alternatively, you can jump and time it just right to grab it from the ground.)
 * In the AntAgonizer's Lair, next to her throne (just north of Canterbury Commons)
 * Inside Jocko's Pop & Gas Stop
 * There are two in Dukov's Place; One in his bedroom and one in the Nuka-Cola Machine on the other side of the room.
 * There is one in The Republic of Dave; In the Capitol Building - on the safe on the right side of Dave.
 * Vernon Square East inside down a dead end subway tunnel there is living quarters with a safe and Quantum on the shelf.
 * There is one in Old Olney's sewers; in the sleeping champers on the left side.
 * NW of the Super Duper Mart, along the river, you'll find a destroyed bridge. Go across the bridge until it ends and jump into the water. Swim just a bit further to the next section and look around, you should spot many Nuka-Cola bottles floating around the surface, and among them, a Nuka-Cola Quantum.
 * To the Southeast of Fort Constantine is ruined building with a workbench, a bed, some Shishkebab schematics and a bottle on the roof. It's about halfway between the bomb storage building and the Satellite towers in the distance.
 * In Vault 92, in the living quarters past the male room. You can see the bottle behind the window.
 * In the Deathclaw Sanctuary, near the Endurance Bobblehead.
 * In the Yao Guai Tunnels.
 * In the Raiders Outpost.
 * In Fort Bannister's Commanding Officer's Quarters, on the ground in the scientifically themed area.
 * In the Lincoln Memorial Maintenance room.
 * Right behind the Nuka-Cola Plant inside a turned over truck.
 * At Rockbreaker's Last Gas, on top of the left-hand Nuka-Cola vending machine.

Rewards
Sierra pays you for them (40 caps each). Once you give her enough to fill her Nuka-Cola Vending Machine, she gives you the Schematic for the Nuka Grenade. In the future, she will also make you a Mississippi Quantum Pie if you bring her the ingredients.

Giving the bottles to Ronald Laren results in a loss of karma (150?) and double the caps (80 caps each) if you succeed in the speech check, otherwise you get 40. Once the quest is complete (if you gave him 30), he goes next door straight away and starts making moves - only to have Sierra completely misunderstand his advances.

For maximum money, it's possible to give 29 bottles to Ronald, and 30 to Sierra. However, a total of 59 bottles is a difficult achievement and will make it very hard to make any Nuka Grenades or Mississippi Quantum Pies as Nuka-Cola Quantums are semi-rare.

Bugs

 * Sometimes, Sierra Petrovita will run around her home in "fleeing" mode for a random period of time. In some cases, it will be absolutely impossible to talk to her. Reloading a save will not always fix this. It appears to happen randomly, but known causes include the player killing an NPC that she likes (Ronald) or having a hostile NPC follow the player into her house. Bringing Fawkes into the house also seems to trigger this. Often there will be a random encounter outside of the house - try to kill everything before entering.


 * The quest never updates after you get the manifest from the Nuka-Cola Plant Factory Floor. The quest counts the computer terminal that is located in the same room as Milo the Shipping Foreman as the manifest. Just use the Terminal, it isn't locked.


 * If the Black Widow dialogue option is used, Ronald often ends up dying once he reaches the Nuka-Cola Plant.

Theft
If you are of the kleptomaniac type, you can steal all of Sierra's Nuka-cola. There are about 70 bottles in total, you will lose about 400 Karma doing so. She doesn't seem too depressed if her prize collection suddenly disappears (provided she doesn't catch you). If she does catch you, she tends to flee. Don't bring Dogmeat because he will attack her if she flees.

After the quest, using the "unlock" console command on the Pristine Nuka-Cola Machine will allow you to steal back your 30 Quantums.