Officer Paul Stark arrests Dwight for walking around with a crossbow. Dwight tried to explain that he was on Trouble-related business, but Paul has never heard of the Troubles. Dwight notices Paul is sweating and asks him why since the day has been cloudy and windy. Nathan shows up and dismisses Paul. Paul grunts and leaves. Dwight and Nathan discuss how ever since Merrill has become the new Chief of Police, things have been rough, especially regarding Trouble-related business.Paul enters the police station and goes to the bathroom. He goes to wash his hands and is shocked to find that his veins and fingernails have turned black. His face turns black and he collapses.Audrey asks Nathan if he can handle the graveyard shift without her. Chris is returning from London and she'd like a date to celebrate. He agrees. Duke enters the station and tells Nathan that he found out that Evi was the one who leaked the info that got Nathan fired from Chief of Police. They agree to find Evi and interrogate her, but then they notice black blood oozing from under the bathroom door.Chris enters the station and kisses Audrey. She asks what has gotten into him, since he's much more cheerful and energetic than he normally is. Nathan calls them over. Paul is dead, his skin has blackened, and black blood is flowing from every orifice. As the group examines the body, Chief Merrill walks up and demands to know what they are doing, and why they are hanging out with a crook like Duke. Duke leaves and Merrill declares that Paul must have been the victim of a terrorist attack involving chemical weapons.Nathan and Audrey try to figure out what is going on. Nathan calls Dwight and informs him of the situation. Duke brings in Evi and says they have a serious problem: she's starting to show the same symptoms as Paul. Merrill sees her and immediately calls for a lockdown. Paul's condition seems to be contagious, so now nobody is leaving the building to prevent it from spreading.That night, Merrill contacts who he claims are the state police and says that he has everything contained. Merrill declares that his plan has worked, as there are no reports of the disease outside the station. A doctor is examining Evi. Merrill orders Nathan to confiscate everybody's cellphones and guns.Chris wants to use his Trouble to convince Merrill to let them go, but Audrey refuses. She hides her gun in an envelope and puts it in her locker. Dr. Hugh Underwood examines Paul's body and says that he can't find any chemicals or pathogens. Nathan contacts Dwight with a radio and updates him. Dwight reports that the state police and CDC have been ordered not to interfere. He promises to find a way to help them.Evi is getting worse and another woman has caught the illness. Nathan and Audrey wonder if it is Merrill's Trouble causing this. They confront him, and he reveals that snipers are positioned to shoot anyone who tries to leave the building. Audrey suggests that he is the one causing this, but Merrill says that he is normal. He goes on a rant about how the Troubled are evil and he is enforcing the law, when his skin blackens. He coughs up black blood and dies.Merrill's body is put away. Nathan takes his cellphone, but it is password protected. He contacts Dwight, who is trying to find a way to avoid the snipers. Audrey finds Merrill's access card, but Nathan reminds her that they can't leave until they cure the plague and deal with the snipers. He agrees to question Evi, while she questions everybody else, since her immunity to the Troubles should keep her safe.Nathan tries to question Evi, and she pickpockets the access card without him noticing. She cryptically says that she was working with Driscoll to help Duke. Duke walks in and orders her to explain. Nathan leaves and Evi says that Duke is special. Duke angrily orders her to cut the riddles and talk straight, but she won't, even though she is suffering from the disease. Duke leaves and she sees gunmen through the window. She contemplates the access card.Audrey questions Nikki Coleman, who came to the station to fill out some building permits. She is extremely nervous and says she doesn't know what is going on.Evi uses the access card to unlock the front door and steps outside, ordering the snipers to answer Duke's questions. Duke calls out to her and begs her to come back. Evi yells that if they don't talk, then she will, but she is shot. Horrified, Duke rushes out and carries her inside. The snipers aim at him, but receive orders not to kill him. Duke asks Evi what she was thinking. She apologizes and dies. Duke is livid and Nathan is forced to knock him out to keep him from doing anything stupid.Audrey realizes that Nikki met with both Paul and Merrill. The disease has spread to more people, including Chris. Chris uses his Trouble to entrance Nikki. He wants to leave, confident that his Trouble will protect him from the snipers, but Audrey warns that he will be shot before his Trouble has a chance to work. She asks what has changed since he was in London. Chris angrily yells that he wishes his Trouble worked on her. She is disgusted and walks away.Audrey is sure Nikki's Trouble is causing the disease and questions her, finding that Nikki's husband is abusive.Chris' Trouble makes more people fawn over him, including Dr. Underwood. Underwood assures Chris that he can save him if they can escape and get to a hospital, but they need a gun. Chris retrieves Audrey's gun.Underwood uses the gun to hold everyone (except Nathan and Duke, who are in another part of the building) hostage, revealing he is Nikki's husband. He notes that he hasn't caught the disease and mocks Nikki, saying that even after she has gained a superpower she still can't raise a hand against him. Chris is regretful that his plan has gone wrong and tries to get Underwood to stand down, but his Trouble isn't enough. It only makes people like him, not obey him. Underwood assures him that he will keep his promise and save Chris. He threatens Audrey, asking why she isn't sick.Nathan locks Duke up in a cell. Dwight calls him and warns that the snipers are apparently planning to storm the building and kill everyone.Underwood prepares to execute Audrey as Chris begs him to stop. Audrey says she's figured out how Nikki's Trouble works: she has been repressing her pain and anguish from her abuse and now it is leaking out like poison. Nikki finally decides to stand up to her abusive husband. He tries to threaten her, but she tells him to go to Hell as the poison spreads through him in a matter of seconds, killing him. As her repressed emotions have all been let out, everybody else is cured of the disease. Nikki is sad about killing Underwood, but Audrey assures her that she saved everybody. Nathan comes in and warns about the coming attack. They prepare to arm themselves.Dwight bursts through the door with the snipers on his tail. The snipers open fire and a bullet grazes Dwight's neck. The snipers retreat. Nathan asks how they are still alive, since there was no way the snipers could have missed from that distance. Dwight reveals that he was wearing a bulletproof vest. His Trouble is that bullets are attracted to him, which is why none of the bullets hit Nathan. Nathan thanks him.As the dead are carted away, Driscoll arrives and offers condolences about Evi's death. He says he will answer Duke's questions... if he proves himself worthy.Audrey asks Dwight to use his skills to make Evi's death look like an accident or suicide. Nathan is wary, but relents.Chris apologizes to Audrey for almost getting everybody killed. He admits that he took advantage of his Trouble in London, and he let it go to his head. Chris sadly says that it is for the best that they break up and he live in seclusion. Possibly, when the Troubles end, he will be worthy of her.