Half Life 2 episode 2 episode 1

Gordon upgrades DOG to look cuter, and he and Alyx forget their objective in favor of leisure activities. After being ambushed, Gordon joins the Combine just for the perks. G-Man warns of an enemy even the Combine fears, and just when it looks like the end of the world, there is a mysterious heroic counterpart to the Combine who can help them. Contains references to spoilers.