
Naval Criminal Investigative Service Special Agent Leroy Jethro Gibbs leads a group of colorful personalities in investigating crimes -- ranging from murder and espionage to terrorism -- that have evidence connected to Navy and Marine Corps personnel. The team includes MIT graduate Timothy McGee, Ellie Bishop, who specializes in international threat assessment, charismatic and unpredictable Nick Torres, and forensic psychologist Jack Sloane. Dr. Donald "Ducky" Mallard brings his vast experience in forensics into play to help solve cases.

After a body is found at an unmanned aerial vehicle testing site, the NCIS team must determine if the death was murder or an accident; Palmer carefully interviews medical examiner assistant candidates.

The lead suspect in a murder investigation is a woman that Gibbs' friend met on a dating site; Sloane has a secret admirer on Valentine's Day.

The team tries to piece together how a retired Navy officer obtained a rare and valuable coin.

The body of a well-regarded Navy technician is found floating in a lake, which isn't far from where a popular community event takes place; Sloane's daughter makes an unexpected request.