Rossi and the team present one of the longest-tenured serial killer cases to college students, taking the class through a nearly 20-year chase for the murderer.
When a cartel kidnaps a senator's daughter in Mexico, Lillian's investigation reveals a hitherto unknown connection between the cartel and her father.
When secretary of the navy Sarah Porter learns her daughter has been kidnapped, Gibbs's team partners with the FBI to track the case, determine a motive and bring her home.
Russell borrows Adam's holiday present idea, and Audrey attempts to make people laugh in a bid to prove she's the funny one in her relationship.
Ray waits to see if Belikov will be released from prison and encounters former clients at a benefit. Teresa battles postpartum depression while Mickey tries to convince the DA that he was behind the Minnassian massacre.
