Nick Potter leaves his law firm to join the New York District Attorney's office which is currently investigating a known drug dealer. Meanwhile, Sara Finn loses key evidence for her case. Soon an assistant D.A. is gunned down and it turns out that another A.D.A. might be involved.

Finn has to investigate why a mother said her daughter was dying of cancer because the autopsy done after she supposedly commited suicide proves otherwise. Potter's friend is arrested for cocaine possession, but when his friend comes to him for help, Potter sends him to Desmond. Meanwhile, Cabot begins an anti-drug campaign.