Chelsea Vance

Chelsea Vance is the daughter of Captain Vance and is the younger cousin of Alyx Vance. She is a main character in the unoffical Half-Life 2: Episode Four and has appeared in City 17 Street in a cameo appearance. She will be a protagonist in Half-Life: The Series remake.

Half-Life 2: Episode Four
During the Uprising in City 17 and after the abduction of Alyx Vance, Chelsea begins to help escort citizens from City 17 before the explosion at the citadel and the city's possible destruction. She later meets up with Gordon Freeman and helps him along with Barney Calhoun get to the train station. She boards the train with Gordon and Barney and they escape City 17, although the train derails after being attacked by a gunship.

She doesn't appear in the sequel Half-Life: White Forest.

City 17 Street
Chelsea made a cameo appearance in City 17 Street in one episode broadcast in April 2009. She was part of a parade in City 14 celebrating two years of freedom from Combine oppression.

Half-Life: The Series (Remake)
In the remake to Half-Life: The Series, Chelsea will replace Alyx Vance's role. Following Alyx's disappearance after the events of Half-Life 2, Chelsea teams up with Gordon Freeman to escape from City 17 and try and find her.

Trivia

 * She appears in a script for the unreleased Half-Life 2: Episode One Movie.
 * As her appearance in City 17 Street chronologically takes place years after her appearance in Episode Four, it means she survived the train crash. However its never revealed in Half-Life: White Forest how she had survived as only Gordon Freeman and Barney Calhoun appear in the wreckage.