We Have a Situation is the prologue chapter of Underhell. Unlike the main story which is survival-horror, the prologue is more action packed.
*Due to the "No Spoiler" policy, this article only reveals parts of the story and does not contain all details regarding it*
On the day the Prologue happens, September 13th, 2013, a group of armed hostiles seized an urban hospital in the City, causing a situation. Jake Hawkfield is called in to deal with the terrorists, saving hostages if he can. Eventually he found a secret entrance through the sewers that the terrorists had used to gain access to the building and tracked them down.
After discovering the terrorist's secret entrance, Jake ventures through layers of defense in the City's old garbage sewer system. Apparently, the attackers had taken the opportunity to breach the Hospital by studying the garbage disposal of the city. Jake emerges to a system of subway tunnels, narrowly dodging the trains and had managed to wipe out terrorist resistance in the area. He then follows the tunnel up to a station that connects to the City Mall.
Once in the Mall, Jake receives orders from Frank Greene to locate and evac any remaining civilians and take out the terrorists stationed there, friendly SWAT units are continuously inserted to further assist Jake in his operation. Once the last survivor is extracted, Frank contacted Jake and told him there's a bogey (a hostile UH-60 Blackhawk) heading towards him, Jake managed to take it down nonetheless. After wiping out the remaining hostiles, Jake takes an elevator down to the Parking Lot to assist a SWAT squadron pinned down there.
Jake is greeted by a small SWAT division inside the Garage. The group leader tells him that there are more terrorists inside the lot and they have barricaded Lot 3 with armored vehicles and turrets that deters any advance attempts, once the roadblock has been investigated, Jake is summoned to the entrance of the Lot. On his way up, he encounters several unidentified personnel that opened fire on him, which caused him to return fire.
Jake shoots his way up to the main entrance of the Garage. Frank then tells him to wait for back up and then head back in but is cut off when an unknown assailant shot down his chopper with him in it. It is up to Jake to give chase or not (more info on this page can be found on the main article). The Corporal then assumes command and orders Jake to take the armored Humvee to smash the roadblock. The Humvee plows through the turrets and smashes open the entrance to the U.D.R.C. Complex.
Jake then finds himself in the U.D.R.C.. The complex was crawling with terrorists, but Jake manages to eliminate them all. Later on, Jake finds a hostage on the second floor of the facility. He escorts the hostage towards the blast door on the first floor so he could open it. After the hostage opens the door, he mentions a character named "Mia", claiming that "only she can stop this". Jake then proceeds through the blast doors and meets Danko, one of the hostile team leaders. Jake managed to kill Danko and his team. He then enters deeper in the complex, during the advance, he finds a hostage getting killed in a gas chamber. Jake was unable to rescue the hostage and proceeds deeper in the facility. He soon found a window in the complex, the window had shown a large group of hostages being held at gunpoint. The Corporal then radios in Jake and tells him that he and the other SWAT members are trying to find a way into the complex.
After the radio call, both the windows and doors had shut themselves, and knockout gas was then leaked into the room. Jake then passes out, only to wake up in the same gas chamber the previous hostage died in. He overhears two unidentified soldiers arguing outside the gas chamber, talking about whether exposing Jake to the poisonous gas or not. Soon one of the soldiers opens the valve and the gas was leaked into the room. Jake was then suffocating in the gas chamber, after a minute he somehow broke out of the chamber and (presumably) kills every personnel within the complex, including the hostages, apparently ripped them apart with his bare hands.
Welcome to Underhell
After having broken out of the chamber and brutally killing everyone in the complex, Jake passes out. A couple of hours later, a SWAT team was sent to the Complex to investigate, they found him alive among the many dead and arrested him for slaughtering the entire complex. Jake's lawyer, Micheal, couldn't defend him in court due to a surprising lack of an alibi and Jake was sent to the A.R.C. Detention Facility.