Benson and Stabler are investigating the case of a baby that was left in the back of taxi. When the baby is examined at the hospital, Warner discovers she has HIV. Warner takes a DNA sample from the baby and discovers her mother was Joanne Suarez and is in Riker's prison. Benson and Stabler pay Joanne a visit.
Stabler and Benson discover Joanne gave her baby to her downstairs neighbor to care for. The detectives take Ida and her husband to interrogation for questioning. Ida's husband is the same cab driver that brought the baby to medical attention in the first place. They lied in the beginning because they were afraid of being deported and baby Antonia being taken away.
Benson and Stabler pay Dr. Gideon Hutton a visit at his offices after learning he was treating Antonia for HIV by giving her alternative medicine. In this case, it was yogurt. Munch later researches that Hutton has a website indicating there is no proof that HIV causes AIDS and he practices medicine using this belief. Hutton believes that AIDS is a myth created to make more money for pharmaceutical companies.
After Greylek went to the media denouncing Hutton's practice, his lawyer threatens a lawsuit. The detectives get an anonymous tip about Hutton's practice that leads them to Lisa Ross's residence. They discover Lisa Ross died from being allergic to penicillin. Her mother tells the detectives that Hutton was the doctor who cared for her.
Benson and Stabler suspect their anonymous caller of being Jack Lufton, a teacher who dated Lisa's mother, Susan, shortly after Lisa's birth. Jack admitted that he contracted HIV from Susan during their relationship and she had acted like it was impossible to get sick from it. Susan had passed it on to Lisa through breastfeeding.
After Warner exhumes the body of Lisa, she makes the conclusion that the little girl died of AIDS, not an allergic reaction. Warner rules Lisa's death a homicide because it could have been prevented. Benson is forced to arrest Susan for passing AIDS to her daughter. Meanwhile, Stabler places Hutton under arrest for withholding information from Susan that could have prevented Lisa's death.
Things become heated at Hutton's trial. Warner testifies that Lisa died of complications from AIDS. Meanwhile, Hutton testifies that AIDS is a myth and Lisa really did die from an allergic reaction. He stands by his belief that the disease was created by pharmaceutical companies who were out to get more money.
Susan testifies that the HIV medication she was given when she was diagnosed made her sick and she was not about to subject her own child to the same kind of pain. Greylek then finds opportunity to introduce Susan to people in the courtroom who had treatment to help slow the process of HIV down in their bodies.
As Greylek attacks Susan on the stand for not saving her daughter's life, Susan begins having seizures. In the hospital, Benson breaks the news that Susan suffers from a brain disease often found in AIDS patients. Susan breaks down and says she needed to believe Hutton when it came to her condition, because her doctor would have never lied to her.
Susan, crying, says she cannot believe she let Hutton kill her daughter. She also tells Benson that Lisa isn't the only child who has died while being treated by Hutton. But before Benson can press for details, Susan flatlines.
Because of Susan's confession, Stabler informs Hutton that they are exhuming the bodies of three other children who were his patients. Greylek is determined to prove the children died from being untreated for HIV. Hutton's attorney wants to make a deal with the ADA. Hutton agrees to the five-year prison term, but promises he'll keep spreading his word.
Stabler and Benson are spending an endless night looking through Hutton's medical charts, searching for more patients that he lied to. Stabler comes across something disturbing from Susan's medical charts. She had lied about the time of her diagnosis, meaning her surviving son, Tommy, has a chance of being HIV positive.
Tommy refuses to get tested for HIV, but the doctors force him down. As Stabler tries to lend a helping hand, Tommy kicks him the ribs, breaking two of them. Hutton's lawyer is now representing Tommy. Stabler brings Tommy into the station and books him for assaulting a police officer.
Tommy goes on trial for his assault on Stabler. While on the stand, Greylek pushes Tommy to get tested for HIV. He refuses and he screams at her to stop saying bad things about his mother. The judge rules in favor of the defendant and says the restraining order stays and he doesn't have to get tested. Greylek dismisses all charges against Tommy.
Stabler hopes to change Tommy's mind regarding getting tested. He introduces Tommy to a young teenager with brain cancer. The boy tells Tommy that his parents refused his diagnosis of brain cancer because they were Christian Scientists who believed prayer would cure him. Once the boy turned to medicine, he began to improve. The boy's story begins to make Tommy think about his own health.
Tommy eventually takes the HIV test and it comes back positive. Stabler assures him there are several types of medicine that can keep him healthy and alive for a long time.