At the start of the game, the G-Man speaks to Gordon Freeman in a hallucination-like vision as he pulls Gordon out of stasis and places him on a train going to City 17. When the train arrives, Gordon gets off and proceeds through the Combine's security checkpoints where he is detained by a civil protection officer. Once in an interrogation room, the officer reveals himself to be Freeman's former co-worker and colleague, Barney Calhoun who is working undercover, and helps Freeman to get to Dr. Isaac Kleiner's laboratory. After meeting Alyx Vance, Freeman is instructed by Kleiner to step into a makeshift teleporter so that he can be safely extracted to the anti-Combine resistance base Black Mesa East along with Alyx, headed by her father, Dr. Eli Vance. However, Kleiner's pet headcrab Lamarr disrupts the machine, and Freeman finds himself — after briefly appearing in several different locations — just outside Kleiner's lab. With the Combine now alerted to his presence, Freeman works his way through the drained canal system, avoiding enemy forces and using the help of human resistance fighters to safely arrive at Black Mesa East.