Through 16 seasons, NCIS has been one of the most successful, highest-rated shows on network television. The series is a spin-off from the show JAG, and itself spawned several spin-offs to varying levels of success. Through it all, NCIS kept its success despite casting changes thanks to long-running storylines and fantastic character work.
Mark Harmon has led the cast as NCIS special agent Leroy Jethro Gibbs, with the only other character still there from the start being Timothy McGee and Dr. Ducky Mallard. While characters have left (Tony, Abby) and others have died (Kate, Jenny), the show plugged on by adding new characters and new cases for them to investigate. Here is a look at the best and worst episodes of NCIS, according to IMDB.
10 THIRST (09.06, 7.5) - WORST
The sixth episode of season 9 saw Ducky in a new relationship with a woman that he met online. Part of the disappointment here is that he was no longer dating McGee's grandmother Penelope (Lily Tomlin). Unfortunately, much of the episode dealt with the new woman (Cheryl Ladd's Mary Courtney) making Ducky seem a little off.
When it turns out that Mary was the serial killer after all and she was doing it for Ducky, it was a twist that no one wanted. Breaking Ducky's heart -- even in the name of a twist -- is not a way to keep NCIS fans happy.
9 SWAK (02.22, 9.0) - BEST
Way back in season 2, the dangers of being on the NCIS team played out in terrifying fashion. Tony received a letter and saw a mysterious white powder in it. It was a terrorist attack on the agency, and both Tony and Kate had to be transferred to a hospital. The mystery bacteria had infected both agents.
While Tony and Kate are isolated and helpless, the rest of the team is on a race against time to find who sent the envelope and figure out what the two were infected with before it is too late. The best parts are the moments with Tony and Kate and the two saying their goodbyes when it looked like time was running out.
8 BULLETPROOF (11.15, 7.5) - WORST
The mystery on "Bulletproof" in season 11 was an interesting one. Loved ones, convinced the U.S. was not supplying the troops with proper equipment, bought armor to send to soldiers. However, it killed them the minute powerful ammunition struck the armor. Someone tricked soldier's families into sending them armor that killed them.
This episode was an early case for Bishop, who was now a Probie. A lot of the episode dealt with her thinking Tony and McGee were hazing her when it was just part of the job. It wasn't a terrible episode by any means but was by-the-numbers and nothing special.
7 TRUTH OR CONSEQUENCES (07.01, 9.1) - BEST
When season six of NCIS ended, the team needed to find Ziva, who was being tortured by terrorists. When season seven's premiere "Truth or Consequences" started, a terrorist went to torture someone, and it turned out to be DiNozzo. The season premiere then flipped back and forth in time to show how DiNozzo got to where he is and how he got out of this predicament alive.
The flashbacks show the team trying to replace Ziva, as everyone but Tony believes she is dead. When Tony finds evidence she might be alive, he and Tony end up captured and tortured, and this was one of the most nail-biting episodes in NCIS history.
6 BROTHERS IN ARMS (04.21, 7.5) - WORST
The season 4 episode of NCIS, "Brothers in Arms" puts Director Shepard in the center of the story when an informant she is meeting with dies in a gunfight. Gibbs and his team move into the case and have to find out who killed the informant, knowing that Jenny was too close to the case to see clearly, as she only sees the man she is chasing as the suspect.
The episode painted the Director in a bad light, as she is so obsessed in proving she is right, that she inadvertently led Gibbs and his entire team into a trap. The team and Shepard also reached the end of the episode by hitting a dead end, leaving many fans deflated.
5 Judgment DAY: PART 2 (05.19, 9.1) - BEST
The best NCIS episodes have the team dealing with tragedies. When Kate died, the team dealing with her loss was devastating. The same thing with the loss of Ziva. However, the death that seemed to hit them the hardest was when Detective Jenny Shepard died in a gunfight.
"Judgment Day: Part 2" was the final episode of a truncated fifth season. The previous episode ended with Jenny's death. This episode has Assistant Director Vance wanting to find Franks, who escaped the murder alive while Tony and Ziva try to find out who was responsible. Gibbs and Franks avenge Jenny's death but then the season ends with Vance breaking up Gibbs' team.
4 PHILLY (14.05, 7.5) - WORST
The 14th season of NCIS threw a lot at fans, and not everyone liked what they saw. While most fans had gotten used to Bishop, who became a fan favorite over time, the new season added Nick Torres, Alex Quinn, and Clayton Reeves to the team. That was a lot to take in, and honestly, the one fans took to the least was Alex.
The fifth episode of the season was Quinn-specific. The case dealt with a missing M16 Officer who might have a connection with a murdered petty officer. With Quinn, Bishop and Clayton sent to deal with the case; it was three newbies taking center stage and the beloved originals as background players. The fact that this episode dealt a lot with Alex's past made it skippable for many fans.
3 KEEP GOING (14.13, 9.3) - BEST
While season 14 was not beloved by a lot of fans, it had one of the best episodes of NCIS history as far as IMDB users are concerned. With a pristine 9.3 rating, the reason this episode ranks so highly was that it put Palmer front-and-center.
Through the series, fans watched Palmer grow from an awkward assistant to Ducky into the man that realistically could take Ducky's place as the chief medical examiner. Fans love Palmer, and he was the real star of "Keep Going." When a teenage son of a dead Navy Captain goes ontop a ledge to commit suicide, Palmer joins him there to try to talk him into coming back in. Palmer then opens up about all his fears and insecurities while, unbeknownst to him, the entire team listens in.
2 KNOCKOUT (06.18, 7.3) - WORST
It took a while for Director Vance to win over fans. At the end of season 5, he broke up the team, and in season 6, he seemed to put roadblocks up at every turn, making everyone's lives hard. Of course, everything he did was for a reason, and he was trying to make the team stronger than it ever was, but it was still hard to cheer for him.
That made the 18th episode of season 6 a tough one for fans to care about. This episode was Detective Vance-centered, as he looked into the disappearance and murder of an old friend from his past and hijacked Gibbs' team to do it.
1 FAMILY FIRST (13.24, 9.3) - BEST
The top-ranked episode in NCIS history came in season 13. This episode was the season finale and changed NCIS completely from that point on. In the previous episode, someone bombed the farmhouse of Eli David, and that is where Ziva was located last. Tony wants to rush to Israel when he learned there was a possible survivor.
However, he learns that Ziva was there and died in the bombing, leaving him alone. What makes this episode so strong is watching Tony's heartbreak and loss at this, and then the twist when he learns that Ziva had a daughter with Tony that he never knew. By the end, Tony leaves NCIS to be a father to his daughter, with some hope that Ziva might still be alive.