A teenage boy named Kevin Stanton is shot but survives. His story of being carjacked doesn't check out. Briscoe and Green find out that Kevin spent the evening with his friend Sara Teasdale - who was shot and killed at the same time. Kevin is arrested for Sara's murder, but then it emerges that he and Sara were shot in the apartment of drug dealer Reginald Mathis. Mathis points the finger at his accomplice Oscar Benavidez, but the case collapses because the search warrant for Mathis' apartment was based on an illegal wiretap. Narcotics detective Rivera, with whom the [=DA=]'s office is working on the case, had falsely claimed that the evidence for the warrant came from an informant.

[=McCoy=] and Carmichael discover that Kevin himself is one of Rivera's informants. Rivera did not follow the official protocol for use of an underage informant, and is now covering for Mathis and Benavidez. Kevin says that he was arrested for drug dealing and agreed to snitch for Rivera so he wouldn't go to jail. Rivera tried to use Kevin in a sting operation against Mathis, but Mathis found out and shot Kevin and Sara. [=McCoy=] grants Benavidez a plea in exchange for his testimony. Benavidez says he knew Mathis intended to kill Kevin, so he called the police to try to report it. Rivera denies this under questioning; but privately admits to Briscoe that he did take the call, and chose to risk Kevin's life to benefit his career.

Rivera won't agree to co-operate with [=McCoy=], and Briscoe refuses to implicate him, feeling that Rivera's decision was justified. Instead, [=McCoy=] charges Rivera with manslaughter and then lets him think that Briscoe told the Grand Jury hearing what Rivera said. Rivera accepts a plea to testify against Mathis, and subsequently Mathis gets the death penalty.

!!!This episode contains examples of:
* TheBadGuysAreCops: Rivera is a corrupt detective who put his career above all else and was willing to let Kevin die just to get the credit for catching Mathis.
* FrameUp: Rivera allegedly set up at least two young men for drug offences because they refused to inform for him.
* GloryHound: Rivera was obsessed with the idea of making a huge drugs bust for the sake of his career.
* HalfwayPlotSwitch: The first half of the episode is about the investigation into Sara's death. The second is about Rivera's role in events.
* LeaveNoWitnesses - Presumably the reason Sara was killed was to prevent her from testifying about Kevin's shooting.
* OutlivingOnesOffspring: Briscoe and Curtis go to Sara's house to question her about the night Kevin was murdered - and find out from her parents that she was killed the same night.
* ShoutOut: A character in the episode is named after the poet Sara Teasdale.