Briscoe and Curtis investigate the death of Michael Sutter, a severely disabled boy who was quadriplegic and had a brain injury. His parents Lois and Joe, and teenage sister Stephanie, are all suspects - but none of them were at home with him when he died, and they all have alibis. Michael initially appears to have been smothered, until the autopsy shows he was poisoned with hemlock in his lunch at the hospital. Joe, who was at the hospital with him, is arrested. But a witness reveals that Michael's physician, Dr. Lyle Semenko, could have tampered with the food.
Semenko is charged with murder after hemlock is found in his car. Ross learns that he could be responsible for at least 17 deaths at several different hospitals, but the defense gets this evidence suppressed. Semenko's lawyer argues that Michael's death was a mercy kill. He highlights the huge toll that Michael's care has taken on the Sutters, including Lois being driven to an affair and Stephanie becoming angry and resentful. The family all deny that they ever asked Semenko to end Michael's life. Semenko charms the jury and convincingly argues that it was kinder for Michael to die; he was only a child and faced a lifetime of suffering.
McCoy questions why Semenko felt qualified to decide who should live or die. He tells the jury that Semenko chose hemlock (which causes a painful death) rather than another option that might have drawn too much attention to him, then let Joe get arrested and take the blame. Semenko is convicted of manslaughter but not murder. His testimony leads Ross to discover that Lois previously worked with Semenko at a hospital where several of his patients died mysteriously. Subsequently, the Sutters specifically requested for him to be in charge of Michael's care. Schiff points out no jury will convict the Sutters when they wouldn't even find Semenko guilty of murder.
Tropes in this episode:
- Black-and-White Insanity: The defense references this trope, saying that it's the view the law takes, while in reality Semenko faced a much more complex moral dilemma.
- Bury Your Disabled: Dr. Lyle Semenko's defense is that it was a case of mercy kill. The situation is murkier than that.
- Death of a Child: Michael Sutter was 12 years old when he died.
- Mercy Kill: What Semenko claims he did. However, the method he allegedly used with Michael Sutter would not have caused a painless death.
- No Celebrities Were Harmed: Dr. Semenko is based on euthanasia proponent Jack Kevorkian, who is referenced in the episode.
- Offing the Offspring: The Sutters didn't kill Michael themselves, but requested a doctor they knew to be a serial killer, expecting that he'd take care of it for them.
- Serial Killer: When Skoda describes the profile of someone like Semenko, Schiff says that he's essentially another serial killer.
- Sympathetic Adulterer: Lois is having an affair with her tango instructor and was with him at the time of Michael's death. She justifies this as her marriage being destroyed under the strain of caring for Michael.
- Tampering with Food and Drink: Michael's death was caused by poison having been added to his food.
- Troubled Teen: Stephanie has become bitter and resentful about the toll caring for her brother has taken on her family, both emotional and financial (due to his medical expenses she no longer has a college fund).
