Sydney

 is a relic hunter the player will meet when hunting for the Declaration of Independence. If she survives the quest and gets to Rivet City, she will retire from relic hunting and become an ammunition vendor in Underworld. If you get into a fight in the Underworld, Sydney will fight alongside you.

Sydney can also be found dead in Anacostia Metro Station, apparently killed by Raiders. It is not known if this is a bug.

In the Statesman Hotel (rescuing Reilly's Rangers) you'll find a Holodisk from her Father. Show her this Holodisk and she gives you her Sydney's 10mm "Ultra" SMG and a supply of ammo.

(Note: There is an exploit where the player can repeatedly select the option to give her the holodisk, this is done by following the action above, then reinitiating conversation with her. The player then selects "Since we're done now, why don't you tell me about yourself?" >"Nice gun. I've never seen one like that." This makes the "So, whatever happened to your father?" option open up again, which once selected gives the option to give her the holodisk. This glitch has only been experienced in the Xbox 360 version, it is unknown whether or not it is present on the PC or playstation version.)

Equipments
Sydney's 10mm "Ultra" SMG (unique SMG, 35 DAM initially, 50 DAM at 100% CND) There is also an ammo supply in the Ninth Circle, that belongs to Sydney. It requires her key.

Apperances
only appears in Fallout 3.

Behind the scenes
is based on character Sydney Fox from the TV show Relic hunter.

Glitch / Exploit

 * It is confirmed that If you do not talk to Sydney prior to finding the Declaration of Independence she will disappear from the hall at National Archives. You will still get the mission to fend off mutants if you approach her position (The Super Mutants will spawn.) She won't be at Rivet City / Underworld or somewhere else after that.


 * You can use her as a joinable character, if you get her and don't complete the quest of course.

Exploit

 * If you wish to keep her as an extra NPC you can do so easily. She will stay with you as long as you do not complete the Stealing Independence Quest. So do not return to Abraham Washington. A few drawbacks with her as an NPC. She cannot be equipped with any new weapons or armor, she cannot be given any items to hold, she can die permanently, she cannot be told to change tactics or to wait (if you are holding the Declaration of Independence), she has to be manually healed via dialog and she has the health of an average human raider and can be downed quite easily. Overall a decent fighter but more trouble than she's worth.