The episode begins at the press meet where Kate tells informs the crowd that the terrorist is infected and is out there infecting more and more people; and she faints. Megan calls for an ambulance. And they inject her with a medicine. After the injection, Kate is stable. Stafford tells Megan that anyone having fever or cough needs to be quarantined; starting with Kate. Johnson is briefing his team about the breakout. He maps out the six possible places where the terrorist crosses paths with the victims. This could be done as the team has tracked down the places the existing victims had been to before they got infected. But there are 10 victims whose information can’t be traced.
Stafford and Megan are talking to the med team and what to know what ever little information or thought they have about the infection. Next, Megan has kept few of the victim’s brains in glass jars and asks Stafford to see what he could figure out. It looks like the COD is hemorrhage. They are discussing all the stages of internal bleeding and then the final stage, and not more than 72 hours between the first symptom and the last. Kate is kept in the ward with the other victims and she is petrified. Johnson is irritated about the fact that despite having around 100 bodies in the morgue; the team is unable to identify the cause of the infection. Megan tells him that finding the microbe is like finding a drop of water in the Atlantic.
Johnson tells her that it is possible that the terrorist could also be one of the victims that are admitted as he was the first to get infected. Good thinking! The terrorist could be one from the 10 outliers; out of which 7 are dead and 3 are in isolation. And that list has Dani! Meanwhile, Peter is at Dani’s apartment. He makes notes of some of the things he finds around. Meanwhile, in the ward, Kate tries to reassure a terrified mother and daughter. But Trevino knows that they are going to die. He is a creep! He says he wants a glass of bourbon; his last drink! A reporter is chasing Peter for answers outside Dani’s apartment. She tells him that people are frightened. And he is honest about not having any answers. At the lab, Ethan informs the team that the syringes found in that isolated building showed traces of the big 3-heroin, cocaine and meth.
But there was this one syringe that has been wiped clean of prints. Not junkie etiquette. Megan goes to visit Kate in the ward. Kate wants to know about the timeline of this infection-72 hours. Is that for her as well? But she also points out that Trevino had collapsed during the interrogation 4 days ago; then how come he is alive? They run a check on Trevino. Johnson thinks that Trevino is alive because he could be the terrorist. Johnson says that e would have figured out a way to stay alive so that he could infect more people and also that he lied about the places he had been to. Megan thinks that one of the 17 drugs Trevino is taking might be slowing down the inevitable; and they need to find which one. Ethan updates Meagan and Stafford about the tests done on the syringes and he says that they found Interferon-a drug which Trevino too is on.
Stafford thinks that Trevino could be the terrorist. Meanwhile, Peter leaves a voice message for Dani’s mom. Megan tells Peter that he needs to box up whatever he is feeling and get to work, as the city is suffering. Peter snaps at her and says that it is possible that one could do things differently. She tells him that she can’t do it without him. Meanwhile, Bud plays the call from the terrorist. He is calling after hearing Peter call the terrorist a coward on TV. They trace the call to the bar near the hospital. Sam tells Johnson that she thinks that their department thinks that Trevino is their guy. Trevino is not on his bed. They go to the bar. Trevino isn’t there but they find blood on the phone from which the call was made.
At the hospital, Trevino is seen sitting on the ground next to his bed, terrified and crying; telling Kate that he doesn’t want to die alone. Megan and Stafford are comparing the found blood sample with Trevino’s and they aren’t the same. But both of them are on Interferon, only that the killer is taking stronger dozes. Seems that the killer is taking it to stay alive longer, so that he could infect more people. Stafford enlarges the blood samples and from that he identifies the nastiest virus ever found-Ebola. Next, at a meet, Stafford educates the team saying that it is Marburg and not Ebola; which is good news; also its very rare as there only few places on the planet where this string could come from. But the bad news is that there is no cure. Stafford tells Bud and Sam to identify why the terrorist is thriving where he is and what could be the common link.
Stafford tells Megan that they need to find the guy and Megan thinks that he should be trying some experimental vaccine. Curtis visits Kate and she is scared as she is showing all the symptoms. She is scared that she is going to die alone. Megan and Stafford go to get a human trial. They go to the ward. Megan decides on Kate but Stafford chooses Trevino as he is a better subject. And it turns out the Stafford made a wiser choice-Trevino responds negatively and dies! Stafford is feeling terrible. Kate realizes that Megan is a truly good friend. Megan is testing Trevino’s liver and Peter walks in. he has found out every place Dani has been to in the past 72 hours and in that one hour is not accounted for and he feels that Trevino had actually seen Dani somewhere; and that it wasn’t just a pick up line when he told her so. He checks Trevino’s timeline.
And Peter figures out that all this transfer happened in a bus. The only place that people have to touch at the entry and exit points; and it is crowded. They check the security footage of the particular bus Trevino was on. And they see 8 out of their 10 outliers. And they find the first passenger who touched the handrail- the terrorist; Jacob and he has a degree in bio-chemistry and is working on his study on population. It seems that he is an intern at one of WHO’s facilities which stores the strands of Ebola and Marburg. Johnson tells the team that Jacob hasn’t retraced any of his previous clusters, so this time it would be a new place or location or medium.
Meagan and Curtis tell them that 2 of the outliers had a common thing-bed bug bite. None of the other outliers had anything in common. Last, the two outliers were at a motel. And Johnson thinks that Jacob too could be at the same motel. They enter the terrorist’s rooms. The manager tells them that he was sick when he entered and they confirm their doubts. But since he is sicker now, he cannot get too far; and they realize that he is headed to the subway, where again the people touch the handrail. They set off. They find him. He asks them to shoot him so that he could splatter his blood all over. Peter shoots him in his head. At the office, Stafford tells Johnson and Megan that he is fired for stealing a vaccine and then also killing a patient with it. But something strikes Megan. Megan tells him that
Trevino already had damaged liver due to alcoholism and it wasn’t the vaccine that killed him but the bourbon he was drinking as his last wish! And that Stafford’ vaccine could still work! This time they try it on Kate. And she responds positively to the vaccine. Welcome back Doc! Meanwhile, Dani’s mother comes to see her dead daughter and Peter. Kate thanks Stafford and also tells him that since he has lost his lab, he could use the sub basement that is unused. She tells him that till the time he gets a job, he could use the free space and the team could get some free lab work. He accepts the offer! The city is healing. Lacey and Megan watch the news…relieved. She tells Megan that Aiden called and she told him that her mom was out; saving the city and she really did. The episode ends.