Originally started as a spin-off from the hit television show JAG (Judge Advocate General) which followed the life of US Navy Commander Harmon Rabb and Major Sarah Mackenzie, NCIS was an instant hit. JAG shined light on the lives of attorneys working to carry out the justice system inside the military.
Enter Leroy Jethro Gibbs; the lead investigator for a Naval Criminal Investigative Service (NCIS) team. He is investigating Rabb because Rabb is the lead suspect in a murder. Although Rabb was cleared, Gibbs was here to stay.
In the pilot episode of the show, Gibbs teams up with Caitlin Todd, a secret service agent tasked with protecting the President. After some nefarious activity takes place on Air Force One, Gibbs and Dr. Donald Mallard (Ducky), are waiting on the ground at an airport to begin investigating the untimely death of one of the people onboard. After all is said and done throughout the episode, the awkward and quirky bond had been formed between the two. Todd decides she is going to leave the secret service and begin her new career as an NCIS agent.
Todd and Gibbs are joined on their team with the very special agent, Anthony 'Tony' DiNozzo, who is the self-centered, narcissistic, male counterpart. DiNozzo, a former Baltimore Police Department detective joined NCIS and became the senior field agent making him second in command of their team.
Rounding out the team after a few almost cameo-esque appearances, Timothy McGhee joins the team after Gibbs offers him a full-time position on their team. Jumping at the opportunity, McGhee becomes the brains to DiNozzo's brawn and the show starts on a primetime roll.
Case after case, the team solves crimes through strong investigation and forensics. Forensic scientist Abby Sciuto is the secret to the agency's success. Smart, pretty, and sometimes scary, Sciuto provides some of the most interesting and intellectual moments on the show. Daughter-like to Gibbs and sister-like to DiNozzo and McGhee, Abby finds herself doing everything in her power to put criminals behind bars.
Each season follows a specific plot, whether obvious or not, providing steps toward the major season climax where the main story of the 20-plus average episode seasons comes to fruition. The first major story follows Mossad agent-gone-rogue, Ari Haswari, who has an unhealthy obsession with agent Todd and a specific hatred for Gibbs. After multiple attempts, Ari realizes that he cannot intimidate Gibbs, so he goes on the offensive. Ari begins playing a life-threatening game of cat and mouse with Gibbs and in his efforts infiltrates NCIS headquarters in the Navy Yard of Washington, D.C., through a body bag. It is in this episode where Ari's interest in Todd begins to show. After escaping, Ari later returns after he goes deep undercover in a terrorist cell aiming to shoot down Marine One, the helicopter that the President flies on. In this episode, Ari's group kidnaps agent Todd, and in front of her, Ari foils the cell's plans and ends up killing some of them.
It is here where Gibbs begins to start sinking his teeth in, becoming unhealthily fixated on Ari Haswari. Ari breaks into Gibbs's home and steals his Remington Model 700 rifle he used as a Marine Corps sniper, nicknamed a "Kate." Ari takes the warfront with Gibbs to the next level; making it evident his intentions are to kill Gibbs. Todd, as a former secret service officer, falls back on her training and starts acting as a protection detail. After they assume her protection duties are over, Todd is shot and killed and Gibbs is positive that Ari did it.
Mossad, finding out that Ari is off the rails, sends in Ziva David, daughter of Mossad Director Eli David to extract and handle Ari. The viewers are introduced to Ziva and find out that Ari is her half-brother; her father had a child with another woman, and he was raised to be a mossad officer but rather fell to the other side. After Ari will not stand down and is in a position to kill Gibbs, Ziva has to make the tough decision to eliminate her brother by shooting him before he shoots Gibbs. Ziva did not hesitate; she ends up killing her own half-brother and in the process, earning Gibbs' trust.
Director of NCIS, Jenny Shepard invites Ziva to stay as a Liaison Officer from Mossad, and she eventually becomes the final piece to the team's puzzle.
As the team goes through case after case, other issues surface. Director Shepard travels to Los Angeles from Washington, D.C., for a funeral. DiNozzo and David are sent along as security for the director, but are told to take an afternoon off. DiNozzo is happy to oblige by David knows that something seems off–so she has McGhee start tracing Shepard's cellphone. Discovering that there is a Russian clean-up crew in Los Angeles to kill Shepard, Gibbs, and two of their other former teammates who carried out a mission that didn't end as it was expected. The deceased team member left clues to warn them: Oshimida. Oshimida was a codeword from their Russian mission and with the word resurfacing later, drew attention from foreign operatives.
After Director Shepard reaffirms that she meant "take the day off," she calls on former NCIS agent Mike Franks to help her eliminate the Russian bad guys. They take off through the desert to an abandoned diner that her deceased friend owned, unfortunately, they were followed. Franks goes out the back door of the diner to get some water from the tank outside, then the shootout commences. Shepard shoots all of the Russian operatives, but is hit in the process. Franks makes his way back inside, but finds Shepard dead and makes the decision to make sure that the all of the Russians are dead. Franks heads back to his place in Mexico to avoid any unanswerable questions, and Gibbs makes the trip across the country to meet with Assistant Director Leon Vance. Vance is named the new Director of NCIS shortly after, but he wants to dig deeper than what Gibbs does, especially after finding out that his mentor was involved in the shootings. Franks explains to Gibbs that Shepard went out on her own terms, and that it didn't matter, she was dying anyway from medical complications. Gibbs struggles with accepting the situation and harbors blame for DiNozzo and David. Franks helps him get him past that, but DiNozzo and David continue to beat themselves up.
Here is where the show sees its next big change; Vance breaks the team up, and the season ends.
Where it left off last week with Leon Vance taking the helm of the Naval Criminal Investigative Service the show starts in a different direction. The main characters of Tony DiNozzo, Ziva David, Leeroy Jethro Gibbs, and Timothy McGhee are all separated in efforts for Vance to carry out a witch hunt.
Gibbs feels that Vance is punishing the team for allowing former director Jenny Shephard to take off on her own and end up killed by the Russian operatives, little does he know that there is more in play than what is at face value. DiNozzo is sent out to become an agent afloat on an aircraft carrier; Ziva is sent back to Israel to her father, Director of Mossad Eli David, to work undercover for them; and McGhee is sent to the basement to use his tech skills in the cyber division. Gibbs is assigned three new agents, Brett Langer, Michelle Lee, and Daniel Keating.
With the three joining "team Gibbs," Vance lets Gibbs in on the hunt for a leak. Once the plot unfolds, Langer and Lee go on an excursion to a secure facility where Lee calls Gibbs to tell him that it's Langer who is the problem and that he is shooting at her, being the role of the omniscient audience, the viewers are let in on a secret; Lee kills Langer when he confronts her and to make it sound as though Langer is shooting at her, she shoots her firearm off into the servers in the secured building. Langer is killed and the mole problem is over; or so they thought.
Gibbs starts on bringing his team back together and gets both Ziva and McGhee back before DiNozzo is allowed to leave his post as the agent afloat. Working to their favor, a crime is taking place onboard the carrier that DiNozzo is on. A petty officer is expected to have committed suicide by jumping off the aft deck, and Gibbs, McGhee, and Ziva find that the suspected-now-dead petty officer's wife has been murdered in their home. As the episode unfolds, the combined efforts and team dynamic solve the mystery, proving to Vance that the team is better together than apart; reuniting the team for the foreseeable future.
The next major plot twist comes when a Mossad handler is snuffing out a terrorist sleeper cell in Los Angeles, introducing the audience to NCIS: Los Angeles' team. As Michael Rivkin makes ripples and tears through the ranks of the cell, NCIS agents too, work toward the cell in efforts to destroy it. As they complete their duties, Rivkin is told to leave the US and head back to Tel Aviv, Israel. DiNozzo doesn't trust that Rivkin has actually left and has Rivkin tracked, finding that he has scheduled his flight out, but with a long lay-over in Washington, D.C. DiNozzo goes to Ziva's apartment to tell Rivkin to leave, but Rivkin does not want to heed his advice, and it becomes a confrontation resulting in Rivkin's death. Ziva assumes that DiNozzo killed him intentionally and decides that she is going to stay in Israel when it comes time for the team to return to D.C. after escorting Rivkin's body back to Tel Aviv.
DiNozzo doesn't give up on finding Ziva after she takes up Rivkin's post on counter-terrorism for Mossad and is captured by the terror cell she is hunting. Mossad does not attempt a rescue and leaves her to die, but DiNozzo digs deeper. After receiving authorization to try and track her down, he and McGhee are captured by the same cell; however that was part of his plan. Torture ensues and DiNozzo is pumped full of sodium pentathol (truth serum) and begins telling the terrorist leader all about them. Once it gets close to the end of the episode DiNozzo fulfills his plan with Ziva being brought to him and holding an ace up his sleeve. DiNozzo tells the terrorist leader that he has 30 seconds left to live, but is accused of lying. DiNozzo corrects him, reminding him that he can't lie due to the sodium pentathol. The terrorist looks to the window as a sniper round from Gibbs drops him and signals the rescue efforts to move in. They are rescued and returned to the US, but Vance is not sure if he is going to allow Ziva to stay or not. As previously she was the liaison officer from Mossad, but because she has not spoke with her father or anyone else from Mossad, Vance does not know where to begin. He puts her through psych evaluations, which she barely passes. Afterward, he has her contact her father, and she lets him know that she is going to become a full-time NCIS agent, and is going to file for US citizenship; she achieves both goals.
The team goes through some serious moments, including an internet created terrorist cell that includes children being recruited through online chatrooms. Agents McGhee and Ned Dorneget travel to Egypt to an international conference on the terror cell. Dorneget dies evacuating the hotel that the conference is being held at, saving countless lives and making him a hero. His mother, CIA Agent Joanna Teague helps in the hunt for terror cell The Calling leader, Daniel Budd. Budd dies at the hands of DiNozzo who shoots him in the chest, cutting the head off of the snake. The Calling is crippled and collapses at the hands of NCIS.
The next major plot twist comes when Eli David is in D.C. visiting Ziva and the Vance family. The Vance home is hit by terrorists and Eli David as well as Vance's wife, Jackie, are both killed in the episode. It is at this point that Vance understands what drives Gibbs. Gibbs, who lost his wife and daughter to a drug cartel member, hunted him down and used his skills as a sniper to end the man's life. Vance wants to jump on board with hunting the killer down just as Gibbs had, but Gibbs convinces him that the best course of action is to get justice because vengeance isn't as sweet as it sounds.
The death of her father sends Ziva on a personal journey back to Israel. She leaves NCIS accompanying her father's body back home and it's believed that she will take the lead of Mossad. Although she doesn't take the role as the director of Mossad, she does stay in Israel. DiNozzo doesn't want to let her go, in fact, he has fallen in love with her. He goes on sabbatical to track her down, and once he finds her, tells her how he feels. When it comes time to leave, she does not come with him, and the split seems to end like that.
Later in the series, they find out that someone is trying to hunt her down, and they track it to CIA Agent Cort. Cort took over the role of an international arms dealer. Cort has Ziva killed, and they find out that Ziva and DiNozzo have a daughter, Tali. It is at this point that DiNozzo steps away from NCIS to be a father and moves with Tali back to Tel Aviv.
It is here where the NCIS changes to the more modern version of the show, highlighting new agents Torres and Bishop. Torres, a former deep undercover NCIS agent is brought to the team, and finds that working in a team environment is not the worst thing ever, and Bishop, a former NSA agent joins the team. Although she is quirky, she fills the role well. It is with this team that the show continues through currently, leading into the upcoming 17 season with rumors of more plot twists to bring the long-time fans back for another adventure.