Half-Life 2: Episode Four

Half-Life 2: Episode Four (sometimes known as Half-Life 2: Episode One The Movie) is an unofficial to Valve's episodic module and was "released" in July 2006. A sequel followed in October 2013 titled Half-Life: White Forest.

Plot
Taking place in an alternative timeline after the ending of Half-Life 2, Alyx Vance is captured by the Rogue Vortigaunt. Gordon Freeman sets out on a quest to find Alyx and help citizens escape City 17 prior to the citadel's destruction. In the end, he flees City 17 at the trainstation along with Barney Calhoun and Alyx's cousin Chelsea.

Planned sequels

 * See Half-Life: White Forest.

At the end of the script for Episode Four, it was stated a follow up titled Half-Life: The Forest would be released in 2007 (to coincide with Half-Life 2: Episode Two's release that year). However as the writer concentrated more on spin-off City 17 Street, they didn't work on the new sequel to Episode Four.

In October 2013, a sequel was released titled Half-Life: White Forest which was split into several episodes and was made for the Halloween Season. It follows directly from the plot of Episode Four with Gordon Freeman and him finding Alyx Vance.