Original: The first '' expansion '' sequel , Half-Life 2 : Episode One , takes place immediately after the events of Half-Life 2 , with the player taking on the role of Gordon Freeman once again and with Alyx Vance playing a more prominent role . Half-Life 2 : Episode Two continues directly from the ending of Episode One , with Alyx and Gordon making their way to White Forest Missile base , the latest hideout of the resistance .
Simplified: It is also available in The Orange Box , along with Half-Life 2 : Episode One and Half-Life 2 : Episode Two ( sequels to Half-Life 2 ) , Portal , and Team Fortress 2.Half-Life 2 : Episode 3 is currently in development .