Moira Brown

 is an eccentric inhabitant of Megaton, and the owner of the Craterside Supply store, also in Megaton. She wants the Vault 101 Dweller to help her research a guide to the wastelands that she is writing, doing tasks such as scouting a nearby Super Duper Mart for food and medicine, or contracting radiation poisoning to study ways to treat it efficiently.

Moira was born in 2253 in the trading community of Canterbury Commons, but ended up settling down in Megaton.

Personality
Moira's personality is extremely cheerful at all times, often excessively so; she takes as much delight in talking about what she's doing as possible. She remains inappropriately cheerful in even the most serious of circumstances. She is also extremely gullible. Almost every time after completing a mission for her you have the option to make her believe something completely ridiculous. Two perfect examples is after finishing the mission from the third chapter of the book where you must retrieve archives from a library filled with Brotherhood of Steel Paladins and Raiders. After returning with the archives, she asks you about the library's condition. A dialogue option will then appear that tells her the librarian is on duty and that you would have brought her a gift, but you forgot your library card. She'll then believe that the library was untouched by the war and is still up and running.

Related quests
Moira wants you to do some dangerous research for a book she is writing entitled The Wasteland Survival Guide. One benefit of one of her sub-quests to complete the Survival Guide is a beneficial mutation that causes the player's limbs to regenerate when suffering from Advanced Radiation poisoning. This may in fact be a predecessor to a sort of ghoul mutation.

At multiple points of this quest line you can attempt to convince Moira that writing the guide is pointless and that she should center on more important things. The first chance is at the very beginning of the quest chain that works off your Speech skill. If you fail your next chance is after you have completed the first chapter of the guide, it does not seem Speech is brought into effect this time around, it just seems a "lucky guess" as to which reply option you choose while talking to her. If you do convince her to stop writing though, you will gain negative karma, and the Dream Crusher perk which causes anyone attacking you to have 50% less chance of scoring a critical hit. It also causes Moira's mood to mellow out and focus on her store, thus giving the player a discount on all items she sells (however this discount is negated if you enter the buy/sell screen through the house upgrade speech option). Her repair skill also increases from 52% to 72%.

If the player character helps Mr. Burke detonate Megaton's nuclear bomb in The Power of the Atom quest, Moira survives the blast, as she was outside of town researching for her guide. She even remarks on how an experiment of hers, a Nuka-Psycho hybrid substance, might be responsible for the explosion. However, the massive exposure to radiation transforms her into a ghoul. If the player has been to the Underworld, she will take residence there. Otherwise she moves to Rivet City. She does not appear to know she's a ghoul at first, but even if the Vault 101 Dweller points it out, her sorrow is extremely short-lived as, typical for her personality, she optimistically realizes that she's always wanted to run some experiments on ghouls and can now use herself as a subject. Moira will still offer the quest The Wasteland Survival Guide after she becomes a ghoul. Curiously enough, if she becomes a ghoul her voice will not have the raspy trademark of a typical Wasteland ghoul (this is likely due to the additional work that would have been involved in re-recording all of Moira's script). If Megaton is destroyed after you've either completed The Wasteland Survival Guide or convinced her to abandon it, she continues to behave as if she is still running her store; you will not be able to tell her she's a ghoul, she will still be able to repair equipment (the only dialogue option apart from The Replicated Man) but not sell or buy, and she appears to remain at the Megaton Ruins permanently.

Appearances
appears only in Fallout 3.

Trivia

 * her personality and appearance are similar to the character Kaylee from the tvshow Firefly.