Years after the Black Mesa Incident (from the original Half Life game), the mysterious G-Man summons Gordon Freeman from his induced slumber. Placing him on a train, Gordon finds himself in "City 17", one of an unknown number of 'urban centers,' where humans are kept in an Orwellian pseudo-slavery by a mysterious alien race known as the Combine. City 17, possibly located in eastern Europe, is overseen by Dr. Breen, a former administrator of Black Mesa who, after arranging the surrender of Earth to the Combine, was rewarded with a leadership position. Humans are now half-way oppressed by themselves. Prisons, concentration camps and urban centers alike are controlled by the Combine Overwatch, members of a somewhat voluntary military in which participation is rewarded with various benefits such as with better living conditions. People are also attracted to it because they would like to feel like being part of something greater then themselves, and also because they can get away with physically abusing tormenting, and killing the civilians. A resistance stirs in the shadows... a large system of underground railroads are in place. The populace is on the edge of total rebellion. What they need is a little inspiration, and a little push, and Gordon Freeman may be just the man to provide it...

G-Man:
The right man in the wrong place can make all the difference in the world.