Gael notifies Phillips that the toxic substance has been released into the ventilation system of the hotel. Meanwhile, Michelle grills Alvers. She learns that there are eleven more vials of the virus, but Alvers does not know the locations where they are to be released. Michelle gives Tony the news. He is shocked to find out that she is inside the hotel. He orders her to leave the building, but she refuses.
Jack tries to get Amador to reveal who he is working for. Amador is willing to die rather than tell him. Chappelle calls Jack with information about the eleven other vials of virus. Jack handcuffs Amador to a rusty pipe. He and Chase discuss that there may be a possibility of containing the virus inside the Chandler Hotel.
Tony briefs Dr. Nicole Duncan as she heads to the hotel with her team. Chappelle tells Tony that no one is to leave the hotel because that may spread the virus. He orders that anyone attempting to escape will be shot and killed.
Michelle arranges for her team to shut down hotel operations and jam cell phone signals so that no one can make contact to the outside. This is to prevent a mass panic. Michelle apologizes to Gael for putting his life in danger.
Phillips asks a bellhop named Margolis to stay on after his shift. Phillips doesn't let on the seriousness of the situation.
Amador manages to loosen the rusty pipe and release his handcuffs. He sneaks out of the nightclub. Kim calls Jack. She is monitoring Amador from her computer's tracking locator because Jack had placed a transponder in the bandage on Amador's hand. Jack and Chase head out to follow him.
Palmer orders Wayne to notify the California governor of the virus at the Chandler Hotel in case he needs to mobilize the National Guard. Sherry tells Palmer that Julia confessed to the police that Sherry was involved in Milliken's death. She had told the police that she was with her ex-husband at the time. Sherry threatens Palmer to corroborate her story or else she will disclose that she was acting on the President's behalf with regards to Milliken.
Amador gets in his car and drives away from the nightclub. Jack and Chase call Tony as they follow Amador. They are hoping Amador will need his boss to help him escape. Jack says that the virus may have been altered, so there is a possibility that Michelle will have a chance of survival.
Amador calls his employer, Stephen Saunders. Saunders asks whether Jack was one of the agents interrogating him. In order to avoid being followed to Saunders, Amador cuts a sharp U-turn and takes another route.
Saunders hands one of his henchman a cell phone. He instructs the man to release the vial of virus when the phone rings twice.
Concerned about Michelle, Tony questions Dr. Duncan about the potential fatality rate. Dr. Duncan has no answers about Michelle's fate.
Michelle and Gael find that the entire hotel is contaminated. Gael begins to show symptoms when his nose bleeds.
Since the virus is supposed to have a fourteen hour incubation period, Michelle wants Alvers to tell her what he did to alter the virus. He promises to tell her if she kills him once the symptoms start.
Wayne warns Palmer that Sherry will be arrested unless he backs up her alibi. Wayne argues that he must protect Sherry or lose his Presidency. Palmer refuses to lie.
Michelle calls Tony to let him know that Alvers admitted to adding an accelerant to the virus to shorten the incubation period. Gael is already showing symptoms. Tony begins to get emotional, but Michelle stops him.
Margolis the bellhop questions Phillips about what is going on. Phillips evades the truth. Margolis goes searching for an exit.
Michelle calls the quarantined Gael to check on his health. She tells him that NHS will soon send in a doctor. Margolis sees Gael and overhears his conversation. Panicked, he pulls a fire alarm. Margolis opens a drawer to grab a set of keys and he finds a gun. He takes it.
Phillips tells Michelle that he thought the fire alarm was disconnected. Michelle orders the agents and hotel workers to prevent the guests from exiting by blaming it on a false alarm.
Amador lets Saunders know that he's not being followed. Saunders gives him the location where he can come in. Meanwhile, Kim tracks Amador's movement and gives Jack the coordinates. Jack instructs her to send for the follow teams.
The hotel guests start to fill the lobby, and Michelle directs them back upstairs. One man demands to be told what is going on because he is prohibited from leaving the building. Another woman says that she saw people with gas masks outside. Michelle lies and says that a toxic substance was released outside the hotel. She tells them that it is safe inside the building. Phillips alerts Michelle that someone opened a fire door on the west side of the hotel, and Michelle goes to search for that person.
Michelle comes upon Margolis trying to unlock a door. He pulls his gun on her. Michelle tells him the same story she fed to the other guests, but he doesn't believe her. She finally admits that there is a toxin inside the hotel and that everyone will be sick. Michelle warns Margolis that he will be responsible for spreading the disease if he leaves the building. He calms down and gives her his gun.
Phillips calls Michelle. One of the guests has started to show symptoms. The woman is bleeding from her nose and mouth.
Wayne brings the Los Angeles Chief of Police in to see Palmer. The President tells the officer that Sherry was with him when Milliken died. Palmer goes to Sherry to give her the news that he corroborated her story. Yet he is still furious about what she did. He says that he despises both Sherry and what he was forced to do in her favor.
Jack and Chase watch Amador walk from his car to another waiting car. A man in the car hands Amador a briefcase. Inside the briefcase is a bomb. Jack watches as the car explodes, and he rushes to the wreckage. Jack's cell phone rings. It is Saunders, but Jack doesn't know him. Saunders threatens to release eleven other vials of the virus in return for Jack's help. "I need you to put me in touch with a friend of yours," Saunders says.
Chaos ensues when a number of the hotel guests begin getting nosebleeds. One of the irate people throws a trashcan at the front door and smashes the glass. Michelle fires her gun into the air to make the man move away from the window. She threatens to shoot him if he tries to leave, but he doesn't believe her. As the man makes his way out, Michelle fires two shots into his back. The other guests are in shock.
Jack calls the President and explains that the man holding the virus wants to speak to him. They will probably have to give in to the man's requests. Saunders tells Palmer that he will release the virus and kill a good portion of the American population unless his demands are met. Saunders says that he will call Palmer again.