context: Prologue: "Once the infection hit, there was little time to react. People did what they could but, since no one was immune to the effects of the virus, authorities were ultimately helpless as the virus rapidly spread. All who became exposed and survived an initial attack began their own relentless quest for blood, attacking and feeding upon the innocent. There was no vaccine, no known reports of individuals made immune. Neighborhoods and entire cities were wiped out. The very fabric of civilization was breaking down before our eyes. Many surviving humans like us were left to fend for themselves, moving around during the day and hiding at night, barricading themselves inside secure buildings. Others formed vigilante groups or became hunters, swordsmen who were tracking down and killing the infected. We were lucky when we managed to find a refuge, a place where there was some food and shelter, a place where we could survive until we could be rescued. But with the location of our refuge no longer being safe and the chances for rescue becoming more and more remote, our options were running out. It was now us 'Against the Dark.'"Morgan (Danny Midwinter) and Dorothy (Jenna Harrison) have been holed up for the past three weeks at the medical complex where Dorothy was once a student intern. Dylan (Daniel Percival), Ricky (Stephen Hagan), Amelia (Emma Catherwood), and Charlotte (Skye Bennett)have come into the hospital looking for penicillin to treat Charlotte's pneumonia. Four hours before dawn, the two groups run into each other and decide to band together. Besides, they have to get out of the hospital before the generator fails and the main security door becomes permanently locked, and Dorothy is the only one familiar enough with the layout to get them to the door. Meanwhile, outside the hospital, Tao (Steven Seagal and his group of vampire hunters are fixing to enter, kill any vampires they meet, and search for survivors. They had better move quickly, however, because Lieutenant Waters (Keith David) has been given orders to "sterilize" the area at the crack of dawn. Fighter jets loaded with bombs are standing by, just waiting for the command to take to the air.Fortunately, Dorothy knows that all the corridors in the complex eventually lead to the security exit, so they start wandering down corridor after corridor, stepping over bloody body parts and fending off vampires who always seem to come at them one at a time. First to fall is Dylan when he goes into a bathroom to wash his hands and gets carried away by an uninfected surgeon (Claudiu Bleont) looking for humans to feed to his infected daughter. The hunters catch up to Morgan and help him kill a vampire. Together, they then rescue Dorothy from becoming some vampire's dinner, as well as Charlotte when she stops to nap. They also rescue Dylan just as little Sophie (Andreea Ungureanu) is about to get a chunk of him. Next to fall is Ricky who, while stoned, wanders through a storeroom and can't tell mannikins from vampires.With 29 minutes left before the generator fails, the hunters and all the survivors finally all meet. The survivors continue to wander the corridors looking for the exit while the hunters clear out rooms and shoot up more vampires. They all meet up again to take an elevator down to the next level. Next to go is one of the hunters, who gets pulled out of the elevator by a vampire just as the door closes and the elevator starts to descend. Suddenly, the elevator gets stuck. Morgan crawls through a hatch and starts to climb down the ladder. The elevator starts up again and knocks him to the bottom of the shaft into a pool of water where he is attacked by a vampire interested in his jugular. When the vampire tries to climb through the elevator hatch, Tao shoots him. The elevator starts up again, and the doors open. Tao gives a gun to Dylan and tells him to take Dorothy, Amelia, and Charlotte to the exit and then to head south to the nearest safe camp. Then he and his hunters go back to kill more vampires. When one of his troops gets bitten in the neck by a vampire, Tao does the only thing he can do...run a sword through her gut.Meanwhile Dylan and the girls have turned into yet another corridor, but this time they can see light at the end of the tunnel. Dylan goes ahead to check it out and is immediately set upon by a vampire. Hearing Dylan's gun fire, the girls start to run. Along the way, they meet a young boy. Amelia declares him not infected but, when she reaches out her hand to him, he bites her and runs off. Now infected, Amelia hangs back while Dorothy and Charlotte keep running, fighting off more vampires as they get closer to the exit. They finally make it to the exit and get the door open. Tao and his last remaining troop, Tagart (Tanoai Reed) catch up, but so does Amelia, now fully turned vampire. She tries to convince them to become vampires, too, but Dylan sneaks up behind and shoots her in the back. Suddenly, dozens of vampires come running down the corridor. Dorothy, Charlotte, Tao, Tagart, and Dylan escape through the door just as a generator fails and the door closes, trapping all the vampires inside. The army starts dropping bombs, and the whole place goes up in flames. In the final scenes, Col Waters receives word that the hunters and survivors have made it out alive, Dylan, Dorothy, and Charlotte drive off looking for the safe spot, and Tao and Tagart walk off, no doubt looking for more vampires to kill.
question: What has overwhelmed humanity?
answer: vampires