Half-Life 2 is a first-person shooter video game developed and published by Valve Corporation. Following the period of instability caused by the events described in Half-Life, an interdimensional organization known as the Combine invades the Earth, defeating the human forces. A Combine Citadel is erected in City 17, a town in Eastern Europe reminiscent of World War II ghettos. Dr. Wallace Breen, a human scientist, rules the city on behalf of his new masters. An energy field prevents humans from procreating, and no new children are born. Earth is turning into a grim, oppressive police state.

Meanwhile, Gordon Freeman, the man who was at the center of the events that took place shortly before the rise of the Combine, awakens from his stasis and is inserted into a train to City 17 by the mysterious G-man. Gordon is soon brought into a resistance group, and makes a seemingly futile attempt to bring down the Combine and liberate the Earth.

• Half-Life 2