Aboard Air Force One a Naval officer dies after eating with the Potus, then a Marine officer (connected with AF1) also dies in Georgetown in the same way. Abby identifies the cause, and Gibbs thwarts an attempt to assassinate the PotUS.

During a training jump a Marine dies when his main chute fails to open, and he fails to pull his reserve chute. Kate joins the NCIS team, and they investigate; they identify not only the murderer and his method but also a drug connection.

US Navy commander "Seadog" washes up dead on a North Virginia beach. 2 dead, alleged drug dealers are found nearby. All 3 are shot. NCIS, joined by DEA and FBI, investigate.

A swimmer finds the weighted body of a seaman who has disappeared from a destroyer of the US Navy. The NCIS team investigate; they find a petty officer connected with the victim and the death, and they save the skipper from an explosion.

A hunter finds an aircraft cargo pod containing the mummified body of a Naval disbursing officer who disappeared from his aircraft carrier, as did 1.2 million dollars. The NCIS team correct some old mistakes, and now they make things right.

A chef finds a naked sailor inside a freezer at a restaurant in Rota, Spain, during a port visit by USS Enterprise; shortly afterward at sea another sailor freaks out on the flight deck; soon one of them dies. Gibbs and his team solve it.

Workers find the decomposing body of a man, apparently a submariner, inside a drum of acid. The team treats the case as both a murder and a theft of identity. Gibbs and Kate go aboard a sub at sea, find the bad guy, and save the crew.

A naturalized petty officer of Egyptian descent dies in the US from massive bleeding due to an intestinal blockage caused by emeralds; he had just arrived from Camp Delta at Gitmo. Gibbs and others investigate at Gitmo and prevent a murder.

Two Marine majors supposedly die during a classified operation in an undisclosed foreign country; one of them purports to call home. The team investigate; they encounter much interference, but they succeed, and they reach a happy ending.

A young lady emerges from a shallow makeshift grave in Rock Creek Park, Washington, DC; although amnesic she says that there's no time, that there's a bomb aboard a Naval vessel, and that people will die. A passing driver aids her and calls 911; the Metro PD responds, then calls the NCIS. Gibbs and his team investigate. Kate befriends the victim and takes her into her pad, and she slowly recovers a few memories. Gibbs finds a key, then Abby figures it out, then Gibbs and Tony find a body. The ship in question proves to be ashore and inside a building. The team learn the name of the victim, then she begins to recover more memories than she reveals. Eventually she confronts the person responsible for her treatment, and she drops a surprise on him.

A Naval officer, a SEAL diver, dies of a stab wound after swimming while testing a classified handheld sonar device, which disappears. An anonymous caller reports the murder. Gibbs and the gang find both the killer and the missing device.

A dumpster diver finds a severed leg, apparently from a Marine, believed to be attached to a live person not more than 24 hours earlier; however, the Marine in question, according to records, died two years previously. The NCIS solves it.

A Marine recruiter dies in his office from a single shot; Gibbs and the gang investigate; then a second one dies likewise. The Gibbs group expect another murder, so they set a trap, and it works; Tony and FBI agents capture the sniper.

A Navy dentist from a Naval air station dies of a single shot to his back, apparently in an execution-style murder; the NCIS investigates. Two more men from the same Naval air station soon die identically. Gibbs and company figure it out.

A Marine colonel disappears during an ambush in Iraq, as does $2M in cash; he re-enters the US under an assumed name; the FBI seeks him, and so does Gibbs, with whom he served while on active duty. Gibbs finds him and figures it out.

A foreign agent enters the autopsy room via an unconventional method; he then takes captive Ducky, Gerald, and, later, Kate. He demands evidence pertaining to a body in the room. He eventually asks to see Gibbs, who obliges him; he loses.

The body of a petty officer falls from a ceiling at a nightclub; Gibbs and company investigate; Ducky says that someone dressed the victim after he died. Gibbs finds $40K in cash; he finds the connection between a prank and an inheritance.

A prisoner, who was a SEAL and a petty officer, escapes from Fort Leavenworth while serving time for having killed his wife and a cable guy; the team, seeking to determine where he may go next, consider whether his conviction was wrong.

A guard finds the disemboweled body of an NCIS agent in an elevator; the gang investigate. Gibbs feels responsibility. The victim has pursued a cold case involving a theft of $12M+ from the Navy. NCIS finds the thief and the killer.

A Marine fails to report after a weekend; he's an EOD tech with a critical qualification, so the NCIS investigates. Three other EOD Marines have disappeared in the past eight years. Abby finds the dots, and the others connect them.

Teenagers at play find the body of a Marine impaled on a post; the team investigate. The victim was an armorer at Quantico. Gibbs and the gang solve both the murder and the theft of surplus weapons. An ATF agent takes an unusual part.

A SEAL lieutenant falls to his death, due to a failed fitting in his gear, while rappelling during an exercise; Gibbs and company investigate; the CIA expresses intense interest. Abby and McGee provide answers, and the team solve the case.

With extreme determination Gibbs continues, to the extent of obsession, to concentrate on the unknown terrorist who shot him and escaped. The bad guy reappears, but Kate and Tony disappear temporarily. Gibbs eventually meets his quarry.

A group kidnaps the wife and the young blind daughter of a Navy captain, who, on his computer, receives a demand for $2M. The officer's secretary secretly goes to the NCIS; the Gibbs team find the hostages, kidnapper, cash, and mastermind.

At base housing in Norfolk workers find, inside an underground room, the decomposing body of a young woman petty officer wearing a bridal gown. Gibbs and the gang find both the bad guy and a victim still alive under similar circumstances.

A farmer on a tractor sees an unattended intact Marine helo inside a crop circle on his land. While Gibbs and company investigate, a burned-out cabin turns up, as does a charred body. Locals evade, but the team solve both mysteries.

A seaman discovers the body of a young woman wearing the dress blues of a naval officer at NAS Norfolk. Gibbs and the gang investigate; Ducky sees a mark on the victim's neck, which he connects to a cold case; the team find two killers.

A civilian dies on a Marine bombing range; while investigating, Gibbs finds a second body; other bodies also later appear. The NCIS and the FBI strangely work well together, and the NCIS team work well together, so they produce results.

A woman Naval aviator narrowly escapes an explosion of her car on a parking lot; she was a target of terrorist activity due to her official behavior in Afghanistan. The FBI solves the crime, and the NCIS protects the family of the victim.

A Medal of Honor recipient from WWII turns himself in and confesses to the team the murder of his friend 60 years ago.

While recovering after heart surgery, a commander dies due to an internal flash and the resulting fire without an apparent external cause; the Gibbs team investigate. Abby says it's murder, then she finds a key fact, and the gang solves it.

The wife of a deployed marine shoots and critically injures a home intruder. During the investigation, the NCIS team discovers all may not be as it seems.

Tony goes as an undercover inmate to find out the location of Iraqi antiques stolen from a naval base. He stages a breakout with the suspect to find out the location.

A two-year-old cold case involving a missing naval officer heats up when a reward-seeking private investigator finds the body. NCIS is on the case, while Kate gets particularly close to the suspect.

A coder, officer at the naval hospital, inserts malicious code, creates fake prescriptions and siphons off medicines for the black market. He fakes his own death and vanishes. He is killed and Gibbs investigates the fraud and his killing.

Ducky faces the "meat puzzle" of concurrently reconstructing three cadavers dissected into many small pieces. Ducky IDs one body, and the gang ID the others and a fourth. Ducky is the fifth target, which causes the NCIS team to act.

A woman reports the strangulation of a sailor in his dress blues; the Metro PD responds to a 911 call, finds no body, calls the NCIS, and turns over the case. McGee, Gibbs, and the others seek evidence, and they find it and a solution.

A Marine sergeant dies while hiking with his wife and his best friend, another sergeant; the gang investigate. Ducky finds a wood-fiber fragment, and Abby reconstructs video footage; Gibbs questions, and the team put it all together.

The body of a woman sailor appears in bed with a bartender, who swears that he went to bed with a different woman. Her death is presumed a suicide apparently from a drug overdose. And then another woman dies.

A neighbor of a petty officer opens a package from Paraguay containing two human eyeballs mistakenly delivered to the mailbox of the neighbor. Gibbs and company investigate. Kate and Tony make discoveries in Paraguay, then they return.

A petty officer enters a bikini contest but fails to appear on stage when introduced; later someone finds her body face-down in a toilet bowl in a women's restroom. Tony enjoys his work; the gang pursue the leads and find the killer.

A petty officer reports that someone has assaulted her; the NCIS investigates. The victim has a mental illness and has had an affair with a captain under investigation by the FBI; she soon dies by murder. The team figures out everything.

An NROTC midshipman stumbles over the body of another middy at 02:00 on the campus of their university; a third mid has disappeared, and McGee finds his body. Abby helps. Gibbs finds the killer, then Kate and Tony cuff him.

A hospital corpsman stows his gear in a self-store room; after 10 months he dies in action in Iraq; then the skeletal remains of a high-school friend turn up in his storeroom. Despite local resistance Gibbs and company solve the mystery.

Tony opens a letter, literally SWAK, dispersing a fine white powder; the gang does the drill. Kate and Tony get a free trip to Bethesda. Gibbs and company find both the bad lady and the solution of a two-year-old rape case at the USNA.

Tony returns early, in time to rejoin the team in an investigation of a shooting of two Naval aviators. Tony finds a bomb, then it explodes; Gibbs says that someone has again tried to kill the NCIS gang, which loses one of their members.

The gang mourn the death of Kate; they recall her and deal with her death. Ari puts a round into Abby's lab, and the NCIS gets a new director, who shares a history with Gibbs. Ducky accepts an invitation to an unusual meeting. [Continued.]

Ducky meets Ari, Tony follows Ziva, Ari secretly betrays Israel and Mossad, Ziva passes cash and a fake passport to Ari, Gibbs and Jen seek Ari but miss him, Ari finds Gibbs, and Ziva finds them. The gang attend Kate's funeral in Indiana.

Gibbs regains consciousness, but he's lost his memory since 1991. He starts to remember a few things; Jen helps, then an old buddy, then Ziva. Gibbs gets back his memory and a solution, gives a severe warning, becomes ignored, then quits.

Someone shoots and kills the executive officer (XO) of a Naval vessel, a commander, in his own stateroom; Gibbs and company investigate. However, a shrink (a persistent and presumptuous one) arrives to conduct mandatory psychologic evaluations for all members of the gang, and she accompanies them aboard the ship. Ziva recognizes the spent brass as Russian. Word of the murder spreads fast, for seven international journalists are aboard as guests; one reporter makes a confession and reveals a potential powder keg. The team continue, and they eventually find the solution. Meanwhile, the shrink also continues, eliciting a number of flashbacks, mostly related to Kate Todd, a former member and special agent. Eventually Tony and Gibbs realize who the shrink is, then she submits her report to the director.

At a diner an unknown person with a drawn pistol approaches Gibbs, who deals with him; then Gibbs experiences flashbacks and fantasies, which Franks explains. The next day McGee announces a decision, then the gang gear up and head out.

Tis the season to be hacking. In a Christmas letter to his father, McGee describes in detail a case in which he, Gibbs and the rest of the NCIS team investigate the hackers who are responsible for the Internet going down in the D.C. area.

The NCIS cyber case turns into a united global effort after evidence confirms "The Calling," an international terrorist group that recruits children through the Internet, has been purchasing German S-mines off the black market.

When evidence reveals an NCIS team member is a hitman's latest target, the team must search through old case files to determine who is seeking vengeance.

Tony returns early, in time to rejoin the team in an investigation of a shooting of two Naval aviators. Tony finds a bomb, then it explodes; Gibbs says that someone has again tried to kill the NCIS gang, which loses one of their members.

A two-year-old cold case involving a missing naval officer heats up when a reward-seeking private investigator finds the body. NCIS is on the case, while Kate gets particularly close to the suspect.

The gang mourn the death of Kate; they recall her and deal with her death. Ari puts a round into Abby's lab, and the NCIS gets a new director, who shares a history with Gibbs. Ducky accepts an invitation to an unusual meeting. [Continued.]

With extreme determination Gibbs continues, to the extent of obsession, to concentrate on the unknown terrorist who shot him and escaped. The bad guy reappears, but Kate and Tony disappear temporarily. Gibbs eventually meets his quarry.

A SEAL lieutenant falls to his death, due to a failed fitting in his gear, while rappelling during an exercise; Gibbs and company investigate; the CIA expresses intense interest. Abby and McGee provide answers, and the team solve the case.

A chef finds a naked sailor inside a freezer at a restaurant in Rota, Spain, during a port visit by USS Enterprise; shortly afterward at sea another sailor freaks out on the flight deck; soon one of them dies. Gibbs and his team solve it.

At base housing in Norfolk workers find, inside an underground room, the decomposing body of a young woman petty officer wearing a bridal gown. Gibbs and the gang find both the bad guy and a victim still alive under similar circumstances.

A swimmer finds the weighted body of a seaman who has disappeared from a destroyer of the US Navy. The NCIS team investigate; they find a petty officer connected with the victim and the death, and they save the skipper from an explosion.

Someone shoots and kills the executive officer (XO) of a Naval vessel, a commander, in his own stateroom; Gibbs and company investigate. However, a shrink (a persistent and presumptuous one) arrives to conduct mandatory psychologic evaluations for all members of the gang, and she accompanies them aboard the ship. Ziva recognizes the spent brass as Russian. Word of the murder spreads fast, for seven international journalists are aboard as guests; one reporter makes a confession and reveals a potential powder keg. The team continue, and they eventually find the solution. Meanwhile, the shrink also continues, eliciting a number of flashbacks, mostly related to Kate Todd, a former member and special agent. Eventually Tony and Gibbs realize who the shrink is, then she submits her report to the director.

A young lady emerges from a shallow makeshift grave in Rock Creek Park, Washington, DC; although amnesic she says that there's no time, that there's a bomb aboard a Naval vessel, and that people will die. A passing driver aids her and calls 911; the Metro PD responds, then calls the NCIS. Gibbs and his team investigate. Kate befriends the victim and takes her into her pad, and she slowly recovers a few memories. Gibbs finds a key, then Abby figures it out, then Gibbs and Tony find a body. The ship in question proves to be ashore and inside a building. The team learn the name of the victim, then she begins to recover more memories than she reveals. Eventually she confronts the person responsible for her treatment, and she drops a surprise on him.