The episode begins at a party, where a guy, at the bar tries to buy a drink for a girl standing next to him; Dani. She tries telling him off by saying that her boyfriend is on his way. But he is persistent and she agrees to have the drink. Moments after she takes her first sip, she feels woozy. She gets up and walks. Peter arrives, but she walks past him. He follows her. She walks out of the bar, her world spinning! Just then she gets hit by a car. Peter runs to pick her up and calls for help. But she is gone. Dani passes away. Next, Megan examines the body and tells Kate that she had slight jaundice. She also had a seizure, which indicates that she had been drugged. Peter was right.
Ethan tells them that Peter showed the surveillance tapes, and says that some creep at the bar spiked her drink. But Megan has news. She tells them that whatever the creep gave her was attacking her before the SUV hit her. She says that it is not the regular date rape drug, but something more powerful. Bud and Sam bring in the creep, Marcel Trevino for interrogation. They show him that video and point out that he did not take even a single sip from his glass. Sam asks him what he gave her. Bud tells him that he got the wrong girl this time. Just then Peter barges into the room and attacks Trevino. But just then there is some odd liquid mixed with blood oozing out of his mouth. They rush him to the ER. Peter thinks that as the symptoms are identical, he probably got the taste of his own poison. Megan asks Peter whether Dani could have been involved with this guy as it seems to be some kind of an infection.
Just then another patient is rushed in with similar symptoms; and they figure out that it is not poisoning. Megan says that the morgue needs to be readied as they might be looking at an outbreak. Next, we see dead bodies in a line and Ethan and Megan are examining them. Curtis is there as well. Ethan is worried as none of these guys were at the club. They just don’t know what to do. Kate tells the team that they need to figure out the places where all the victims had been and also who got sick first. Just then Charlie Stafford arrives with his team. He is from disease control. He says that they need to leave as this is icky stuff and they don’t want to get any of it. They are going to decontaminate the area. He tells them that CDC got a request letter from Kate. All the people from the facility are being decontaminated and their blood samples are taken for examination. Just then Bud and Sam walk in, saying that the station too was being decontaminated. They are allowed to go in a while.
Megan reaches her office and finds that the area is being taken care of by the CDC. She notices that there are some changes made and she doesn’t appreciate it. but Charlie tells her that the number of dead bodies have doubled overnight. Charlie says that Megan is emotionally involved with the case and she should not be there. But we know Megan; persistent enough to get what she wants! Charlie allows the team to enter and deal with the case. They find out that one of the dead bodies could be the patient zero. Just then Bud shows a tape to Megan and Charlie, where a masked man is talking into the camera and declaring that a lot of people are going to die. So, it’s not an epidemic but an act of terrorism. Next, there is a meeting and Special Agent Brendon Johnson arrives. But the meeting didn’t turn out to be too useful.
Next, the families of the dead are seen talking to the team. One of the relatives tells Bud and Sam that the terrorist video is all over the internet and her friends in Korea know about it. Next, Bud asks Trevino about the place he has been to in the last couple of days; as he is one of the first ones to get sick. But Trevino refuses to co-operate. Bud tells him that if he doesn’t, then he could make things very difficult for him. Trevino agrees to talk. He tells him about his recent activities. Meanwhile Peter is trying to find about Dani’s whereabouts for the last couple of days. Next, the team tells Brandon that they have found the disease causing organism in one patient only. And that it is being aerosolized. Brendon is going to tell the people their best theory. Megan thinks that it is wrong doing so, but Kate thinks otherwise.
Kate is stitching up one of the dead bodies, when the needle accidently pricks her. But she keeps quiet about it, and washes her hands in the basin; but leaves behind the blood. Meanwhile Brandon is about to give a speech and wants Peter to be on television as he lost his girlfriend; the human angle. Just then Sam and Bud arrive and tell Brendon that they have a lead, a local guy and a website which says that a disease is a cure for the population. It is announced on the television that it is confirmed that it is meningitis! Well, something that’s not confirmed; and Megan and Kate are upset. They are also shocked that Brendon has also announced about Peter and his girlfriend. Kate is still tensed about the needle prick and fears that she could be infected. Bud barges into the house and arrests the local. Lacey is terrified when she realizes that the television lied, and Megan assures her that things will soon be fine.
The local is being interrogated by Brendon, but it turns out that he has nothing to do with it. But with his knowledge, he does know that the breakout doesn’t seem to be meningitis. Megan tells Brendon that at least now he should stop with his meningitis theory; even 17 year old kids are not being fooled. Megan manages to convince Charlie and Kate that they are looking at an exotic virus and it is NOT airborne. She removes her mask. She deduces that blood could be the major mode of contact and as long as they don’t come in contact with it; they are fine. Next, a girl who considers Dani as her sister meets Peter. She tells him that they were from the same foster home. Meanwhile, Bud is sending his family away to some safer place. Next, Sam is going through the video again, and asks Bud to pay attention to the background sounds.
In the video, Sam finds the symbol of a drug cartel that runs in a tight area. They reach the location. They find rotting dead bodies and syringes lying around. They collect the evidences and get them to the lab. Peter goes through the video and sees that the terrorist has blood shot eyes and points out to the possibility that he could be one of the affected ones. They then deduce that the terrorist is the patient zero. He infected himself first and made sure that whoever came in contact with him gets infected. Curtis and Ethan bring the rotting bodies to the lab and are scared about being infected.
Peter tells Megan that the 15 year old girl knew Dani more that he did. Next, Kate is rehearsing her speech and Megan notices that she is sweating. They have a disagreement about what she is going to say and Megan walks off, telling her that she is going to make the biggest mistake of her career by not telling people the entire truth. She is making the speech when Ethan calls Megan and informs her that the antibiotics aren’t working and all the patients are dead. They can’t stop it. Kate is questioned by a reporter and is asked about the mode of transport of the disease. She tells the people that the truth is that the terrorist is sick and is out there; infecting everyone; and she faints. The episode ends.