NCIS is an investigative procedural show featuring Mark Harmon as the wise but by-the-book Leroy Jethro Gibbs - affectionately known just as "Gibbs."
The show revolves around an team which includes Tony DiNozzo, Gibbs second-in-command, NCIS Medical Examiner Donald Mallard (he prefers to go by the name "Ducky"), Ducky's assistant Jimmy Palmer, computer expert Tim McGee, forensic scientist Abby Sciuto, NCIS Director Leon Vance and the newest member of the team - Ellie Bishop.
Gibbs is a Navy sharpshooter who doesn't like revealing emotions. His love life is a mess: after his first wife was killed by a Mexican drug dealer on the last day of Operation Desert Storm, his subsequent romantic relationships were doomed for failure, as none of his next three wives could measure up to the love he had for his first wife. All ended in divorce.
After watching Gibbs' failed romances, Ducky realized he too had a first love that never panned out, which is why he never bothered pursuing romance. He didn't want to go through the pain his good friend Gibbs experienced.
Tony is a former police officer who is a movie buff. Though he too commands respect, he is a bit of a brat who enjoys teasing his team mates. He dates a lot, but there has been only one woman who ever captured his heart - a former NCIS teammate named Ziva. Sadly, she has elected to stay in her homeland of Israel, and he's had a tough time getting over her.
Though Abby has a goth exterior, she is the group's moral conscience and is a genius at her job. Between her skills and that of the computer geek McGee, they cut to the heart of Navy-related crimes.
When Ziva left, Ellie Bishop took her place. As she's the probationary employee, she's in constant learning mode, with Tony acting as her mentor.