You are Adrian Shepard, in stasis since the debacle at Black Mesa. But fortunate for you, a situation occurs where you come of use again and so the G-man comes back to bring you out of stasis. The events in this game happen a bit before Gordon arrives in City 17, the player will start in black mesa-ish base thats still resistent to the combine occupation, from there it will bring the player to a quarry, a soviet submarine base and into the basements of a older citadell where the combine stumbled on ancient alien technology.