Sydney

 is a relic hunter the player will meet when hunting for the Declaration of Independence in the year 2277.

Background
As a child, Sydney was abandoned when her father was killed during a weapons trade off at the Statesman Hotel. She had to wander D.C. alone, but she was able to handle herself because her father had taught her how to handle and maintain guns, and to upgrade them since she was young. Sydney then became a relic hunter and did some work for Abraham Washington.

Effects of player actions
During Stealing Independence the player has the option of recruiting her as a temporary follower. If she survives the quest and gets to Rivet City, she will retire from relic hunting and become an ammunition vendor in the Ninth Circle in Underworld after the PC and Sydney receive their reward from Abraham Washington. The quality of what she sells is a notch above much of the items of other vendors. She will usually have several good condition weapons and will have lots of ammo in stock.

Sydney will remain a follower as long as you do not complete the Stealing Independence Quest.

If you got the Declaration without her help, she may hunt you down, with another treasure hunter named Emaline, in a random encounter and try to kill you. You must encounter her then deny her offer.

If you get into a fight in the Underworld, Sydney will fight alongside you.

In the Statesman Hotel (Mid Level) (rescuing Reilly's Rangers) you'll find A Note from Little Moonbeam's Father, which is directed to Sydney from her father. Show the Holodisk to her and she will give you her Sydney's 10mm "Ultra" SMG and a supply of ammo.

Appearances
only appears in Fallout 3.

Behind the scenes
is a reference to the character Sydney Fox from the TV show Relic Hunter.

Bugs

 * There is an exploit where it is possible to receive an unlimited supply of Sydney's unique 10mm "Ultra" SMG in perfect condition and 10mm ammo. It can be found under the Sydney's 10mm "Ultra" SMG article. (confirmed all platforms)
 * You can't pickpocket Sydney after recruiting her neither during the quest nor after completing it you just get the talk option when crouching. (confirmed all platforms)
 * When she walks into The Museum of History she sometimes gets stuck on the stand where the Dinosaur Skeleton is or on a bench in the same room. (confirmed Xbox 360)
 * Sometimes on her way to Underworld, she will stop halfway through the Museum Station. If you attack her during this situation, you can still talk to her, despite the fact that she is hostile and attacking you. (This can be fixed by 'pushing' her along the hall with all the subway trains.)
 * Sydney may just not be seen at underworld. she may have either been killed on her way to underworld after completing Stealing Independence or she is stuck somewhere on her way to the underworld.(confirmed on ps3)