Jack goes to meet with Dr. Nicole Duncan, the head of Health Services for Los Angeles, in order to bring a Hazmat team to Kyle Singer's house. As he's waiting for her in his car on the side of the freeway, Jack takes out the heroin kit in need of a fix. He ties up his arm and fills the syringe with the drug. But before he can inject himself, a squad of Health Services vans pulls up. Jack hurriedly puts the paraphernalia away. Dr. Duncan gets into the passenger seat and greets him. Jack drives off with the Health Services Hazmat team in tow. Dr. Duncan says that Dr. Macer's estimates are off. She believes that the virus would infect of the population in one week and that it is more deadly than originally thought. Duncan notices that Jack is perspiring, but he fends it off as being overworked. Then Duncan sees the heroin vial on the floor of the car.
Michelle listens to the recorded phone message from the terrorists. She summons Gael over to see a discovery she made about the signal, unaware that he is the source of the scrambled voice. Michelle has figured out that the call was made from inside the United States, and she wants Gael to try to narrow it down. She tells him that Jack is closing in on the location of the virus. Chloe stops Gael to inquire about an audio feed for Jack. Gael says that he must do something else first.
At the Salazar Ranch, Claudia suggests to Hector that he won't want to give up running the business once Ramon returns from prison. Gael calls Hector's cell phone to tell him that Jack is about to discover the virus. Hector gets assurance that their guy Gomez is still on Kyle Singer's tail.
Kyle's father asks his son how he found the money to pay off the rent. Kyle says that he got a tip at the racetrack, and didn't do anything illegal. The father becomes angry, and Kyle locks himself in his room.
Tony briefs his team on Kyle Singer and the possibility that he is holding the virus in what he believes is a bag of cocaine. The boy has no idea what he is in possession of.
As his parents argue in the living room, Kyle puts the cocaine into a gym bag. He goes to leave, but his father stops him to ask what's in his duffel. The father grabs it and finds the baggie full of white powder. Kyle fights with his dad and runs out. The baggie breaks open. A room fan blows some of the powder into the apartment.
Kim exits Tony's meeting and sees Chase talking to CTU associates. She asks why he isn't with her father, and Chase says that Jack sent him to the sidelines because of his relationship with her. Kim is adamant that Jack would have had the same reaction regardless of when he found out.
Salazar has his prison guard contact Annicon because he is ready to talk. Annicon, who is outside the prison, hurries back inside.
President Palmer doesn't believe what is in Senator Keeler's playbook about Anne. Wayne knows that the allegation alone could hurt them even if it is untrue. He asks Palmer to confirm whether Anne has told him everything. Wayne admits to not liking Anne, but he wants to make sure that Palmer knows what he's facing before he steps into the debate with Keeler.
Annicon comes in to see Salazar. Salazar knows that Jack wouldn't reveal the virus threat to Annicon. He tells the lawyer that he will be released in a few hours because of his brother Hector. Salazar's guard whacks Annicon over the head with a baton and strangles him from behind. Salazar watches as Annicon dies. Salazar informs the guard that his son will now be returned. The guard slinks away in shame.
Kyle's parents are arguing over what to do about their son when they see figures outside their window. Suddenly, a buzz saw cuts through the front door. The mother panics and dumps the bag of powder into the toilet bowl. Jack, Dr. Duncan and a team dressed in Hazmat suits invade the apartment. Jack radios Tony that the virus is in the sewage system and could possibly be airborne.
Palmer confronts Anne over what is in Keeler's research. She claims to have told the President everything she knows. Her ex-husband, Ted, was convicted by the SEC for fabricating research at his drug company. Although Ted once testified that Anne knew nothing about it, he is now saying that she was aware of the lies when she reviewed the medical research. Palmer has reason to be suspicious, but Anne says that she told him the whole truth. He says that he does trust her. Wayne calls and says he might have a way to make the whole thing go away. He asks his brother to meet him in the USC auditorium.
Dr. Macer assures Tony that she is optimistic about containing the virus or lessening the casualties based on the speed of Dr. Duncan's team. Michelle informs Tony that the local news has picked up the story on the body being dumped at Health Services. He instructs her to not let the press know anything. Then the prison warden calls with news of Annicon.
Jack lets the frightened Singers know that their son Kyle may have carried a virus from Mexico when he thought he was transporting drugs. They need to be quarantined until more is learned. Tony calls Jack on his cell to tell him that Annicon was killed by Salazar's prison guard. Suddenly, a wave of claustrophobia hits Jack and he clicks off from Tony. Jack rushes to the biohazard shower and quickly rinses his Hazmat suit. He tears the mask off and vomits. Dr. Duncan's team assesses that the powder is harmless and that the Singers tested negative for the virus. She brings Jack the news. He wonders if the virus is being contained inside a living host -- Kyle Singer. Since the incubation period is fourteen hours, the fact that Kyle was in Mexico eleven hours ago and Hector Salazar threatened to release the virus in three hours adds up.
As he exits a city bus, Kyle calls his girlfriend Linda. He needs her to help him get money to pay for the cocaine because his dad took the bag away. She reluctantly agrees to steal money from her parents and meet Kyle at the mall. Following Kyle is the Salazar hired gun, Gomez. Gael reports to Gomez that CTU knows the powder does not hold the virus. He orders Gomez to take Kyle into containment without the police getting him first.
Wayne tells the President that Anne's ex-husband wants money to keep his mouth shut. Palmer refuses to give in to blackmail. Wayne says that Anne will be on the front page of every newspaper, and Palmer can prevent that from happening. Palmer agrees to pay Ted Packard.
Jack informs the Singers that the powder is harmless, but that Kyle may have been infected. Jack gives Tony the number of the cell phone Kyle is carrying, while Mr. Singer calls his son under the instruction to keep him on the line so that they can trace it.
Kyle answers the cell phone and is surprised to hear his father on the other end of the line. Mr. Singer tells his son that he may have contracted a virus when he went to Mexico. Kyle thinks his dad turned him into the cops, but Mr. Singer tries to convince him that he could get sick. Kyle hangs up, but Tony is able to track the location as the Los Feliz Mall. Tony says he can quickly fly a team to the mall to meet Jack. Jack agrees, but makes Tony promise not to send Chase.
Chloe tells Chase that Tony is going to the location where Kyle Singer has been found. Chase is annoyed because he is being cut out of the investigation. He runs out to catch Tony before he is to board a waiting helicopter. Chase argues that he is being made to pay because he is seeing Kim. "Take it up with Jack," Tony says as he walks off.
Gomez follows Kyle in the mall.
Jack drives to the mall with the Hazmat team in tow. His cell phone rings, and he sees on the caller ID that it's Chase. Dr. Duncan notices that Jack refuses to answer it. Frustrated, Chase tosses his cell phone in the trashcan. Kim approaches Chase to tell him that her father will come around. "Maybe you don't know him as well as you think," Chase answers, alluding to the heroin addiction. She says that, other than telling Jack, the only other option is for them to stop seeing each other. Chase is silent.
Tony's chopper lands at the mall, and the security guard reports that Kyle Singer has been spotted. As Jack drives toward the location, Dr. Duncan asks him how long he has been using heroin because she recognized the symptoms. Jack admits that he became addicted while undercover with the Salazars, but that he is not currently high. She doesn't want to turn him in but she is worried about him. Duncan has a responsibility to stop the virus, and she asks Jack not to screw the case up. Jack gets a call from Tony, who says that they are in place to grab Kyle. Jack pulls up to the mall entrance.
Gomez calls Gael to warn him that CTU is about to pick up Kyle. Gael orders him to stand down. Gomez refuses to wait and heads toward the kid.
Gomez walks past Kyle, and brushes against Tony's arm as Tony approaches the boy. Tony tells Kyle that what his father said about the virus is true. Kyle is frozen by the sight of Gomez's raised gun behind Tony. Gomez fires, and Tony is hit in the neck. Kyle flees as the other mall patrons scream in fear. Jack runs in amid the confusion and spots Tony lying motionless on the ground. Jack radios for help with a warning that Kyle Singer is not in custody. He kneels down and presses his hand to Tony's bleeding neck.