A woman named Anna Hopkins is killed in a carjacking. Briscoe and Green recover the car and arrest the thief. But then they learn that the victim, who worked for a medical research lab, was transporting a sample of the SARS virus in her car. Her boss, Dr. Charles Blanchard, suggests she stole the sample because she was planning a bio-terrorist attack. But a friend of Anna claims that Blanchard told her to secretly dispose of the sample by herself.
A SARS epidemic breaks out with several people infected. The "patient zero", Jeanine Williams, is a journalist who previously worked with Blanchard. They had an affair, but she broke up with him; now she believes he deliberately infected her. Blanchard is the father of her young son, who's immunocompromised and in critical condition with SARS. Her son dies, and now Blanchard faces a murder charge.
Blanchard refuses a plea, and his wife Elaine supports him. McCoy and Southerlyn are concerned that Elaine's testimony could sway the jury. She gives him an alibi, and insists that she isn't affected by his affair with Jeanine. When McCoy pushes her for more and more details on the alibi, she breaks down and says she can't forgive Blanchard for killing his own child. Elaine recants her story, but then has Blanchard's lawyer pretend to lure her into "correcting" herself and saying she lied because she was angry about his many affairs. The jury acquits.
This episode contains examples of:
- Age-Gap Romance: Jeanine Williams is considerably younger than Blanchard.
- The Bad Guy Wins: With Elaine's help, Blanchard gets away with everything.
- Contrived Coincidence: Anna Hopkins just happened to be killed in a carjacking at the time when her boss had told her to dispose of a deadly virus to cover up his crimes.
- Daddy DNA Test: Jeanine had one at Blanchard's insistence.
- Death of a Child: The only one to die in this outbreak is a little child.
- If I Can't Have You…: Blanchard tried to kill Jeanine for breaking up with him.
- Manipulative Bastard: Both Blanchards fit this profile.
- Married to the Job: McCoy tells Southerlyn this is why his wife left him.
- Medication Tampering: The outbreak started from a Vitamin B12 injection.
- Middle Eastern Terrorists: Blanchard's defence attempts to claim that Anna was a potential terrorist based on the fact of her being half-Saudi.
- Offing the Offspring: The only dead from this outbreak is Blanchard's son.
- Ripped from the Headlines: Based on the then-recent outbreak of a SARS virus in Asia.
- Rule of Three: The detectives refer to this after three witnesses identify Lamont in a line-up.
