Underhell is an Episodic Story Line Single Player Modification for Half Life 2, based on the SMOD.
In Underhell, you incarnate Jake Hawkfield, a Special Weapons and Tactics Operative, who recently married and moved in with his beloved wife. But soon after those happy events, his beloved wife dies in mysterious circumstances, only leaving clues that lead to believe in a suicide. Jake falls apart, and only his best friend, mentor and boss Frank is here to help him get over his grief.
The mod begins with a wake up call from Frank, ordering Jake to come down to the station. An armed group of elite soldiers have taken control of a hospital and all it's personnel. But Jake will soon realize that it is not a common Hostage Situation...