Sean Cullen

Three teenagers die from drug overdose, and Danny sets out to find their narcotic source and bring the responsible to justice.

When Morland offers to help get Joan and Sherlock reinstated as consultants to the NYPD, Sherlock questions his father's motives. Joan works with the FBI during the investigation of a triple homicide.

When Tony's former partner is found murdered and linked to the Port-to-Port serial killer, Tony remembers his days as a detective in Baltimore, and recounts his first meeting with Gibbs.

As Peter's trial begins, Alicia tries to keep her husband out of jail. Diane and Lucca make an aggressive move to expand the law firm but face opposition from David Lee.

An investigation into a house fire and double murder is hindered by a veteran arson investigator and his colleague, and the case becomes personal for Peter.