Season One
Equal parts JAG and C.S.I., NCIS does a formidable job of blending relevant military headlines with quirky characters who are tenaciously determined to solve a crime--even if it means having to sleep in the morgue to get a few minutes of shut eye. Created by Donald P. Bellisario (JAG, Quantum Leap), NCIS actually began as a two-part episode of JAG in 2003. Later that year, the drama made its full-season debut on CBS. On this six-disc set, which includes all 23 non-JAG episodes plus optional commentary by Bellisario on the first episode, viewers are introduced to an elite squad of special agents, led by Leroy Jethro Gibbs (Mark Harmon). Gibbs is a hard-nosed investigator who doesn't say much. But when he does, an insult usually comes out of his mouth. He's brilliant when it comes to ferreting out the truth, but he's not savvy enough to figure out how to block his ex-wife's nagging phone calls. Instead, he makes do by destroying his cell phone. Gibbs' team is fleshed out by an eclectic and somewhat eccentric set of colleagues, including medical examiner Dr. Donald "Ducky" Mallard (David McCallum from The Man from U.N.C.L.E.), wannabe playboy and former homicide detective Anthony DiNozzo (Michael Weatherly), forensics expert and resident Goth chick Abby Sciuto (Pauley Perrette), and former Secret Service agent Caitlin Todd (Sasha Alexander).

The murder of a peripheral NCIS agent halfway through the season is a taste of what's to come in future seasons when core characters leave the show (voluntarily or not). But in its first year, the show sets up a strong premise that (while not wholly original) is well executed. One of the more stickling aspects of the show is its reluctance to allow Tony to show signs of maturity. At times, he behaves more like a rambunctious puppy than an ace investigator. --Jae-Ha Kim

Season Two

NCIS takes the CSI formula, throws in a good dose of JAG, and comes up with an entertaining series that takes advantage of the actors' likeability. The season begins with the introduction a couple new regulars--agent Timothy McGee (Sean Murray) and assistant medical examiner Jimmy Palmer (Brian Dietzen). And one cast member departs the show by the end of the season. The six-disc set includes all 23 episodes, which aired on CBS during 2004-2005. The show's sophomore year begins with "See No Evil," in which a Navy officer (guest star David Keith) is forced to embezzle millions of dollars, or risk having his wife and blind daughter killed by a kidnapper (played by Tom Cruise's cousin William Mapother). Led by Jethro Gibbs (Mark Harmon), the crack NCIS team comes through to save the day and reveal the mastermind behind the twisted case. Gibbs doesn't display much more emotion this season than he did in the show's debut, but he's just as sarcastic (and even tempered) when being threatened. During one altercation, the mafia threatens to kill his father, brothers and uncles. Non-plussed, Gibbs calmly says that while he has no male relatives still alive, he'd be happy to fax over the numbers of his three ex-wives.

With the help of his ace medical examiner Dr. Donald "Ducky" Mallard (David McCallum from The Man from U.N.C.L.E), Gibbs and his team are almost invincible when it comes to solving complicated crimes. Whether he's piecing together the bones of a body, or performing an autopsy on a crisply burnt poodle, Ducky is matter-of-fact as he talks to his dead "clients." Of his nervous but eager assistant Jimmy, Ducky notes, "He means well, but sometimes I have an overwhelming urge to slap him." This season, viewers get to see the romantic (and slightly gross) side of Ducky as he briefly romances a doctor half this age. Also on hand to aid (and annoy) Gibbs are happy-go-lucky Tony DiNozzo (Michael Weatherly), former Secret Service agent Caitlin Todd (Sasha Alexander), and forensics expert Abby Sciuto (Pauley Perrette), who can solve anything if you say "please" and bring her a Big Gulp to sip. Look for a gentle guest appearance by Charles Durning as a Medal of Honor recipient who wants to turn himself in for killing his best friend and fellow comrade during World War II. While the plot twists won't surprise most viewers, the acting, writing, and spirit of the episode leaves the viewer feeling satisfied. --Jae-Ha Kim

Season Three

With two solid seasons already banked, NCIS returns for a compelling third year with exciting plotlines and a slightly tweaked cast. The show's second season ended with the brutal and shocking death of Caitlin Todd (Sasha Alexander). The first two episodes of this season deal with the aftermath of bringing her killer to justice and examining the emotional impact of her loss on the remaining members of the NCIS team, which is led by Jethro Gibbs (Mark Harmon). The six-disc set includes all 24 episodes, which aired on CBS during 2005-2006. Returning are happy-go-lucky ladies' man Tony DiNozzo (Michael Weatherly, Dark Angel), forensics expert and resident Goth chick Abby Sciuto (Pauley Perrette), medical examiner Dr. Donald "Ducky" Mallard (David McCallum, The Man from U.N.C.L.E), and agent Timothy McGee (Sean Murray). Former Mossad intelligence officer Ziva David (Cote de Pablo) joins the close-knit cast, as does Jennifer Shepard (Lauren Holly, Dumb & Dumber) as the new NCIS director. Working on a daily basis with Shepard initially makes Gibbs wary. Not only is she a former girlfriend, but she also was his underling at one time. Equal parts CSI and JAG, NCIS works primarily because of its quirky cast, which is able to take sometimes regurgitated ideas and rework them into something engagingly watchable. Throughout this season, we will see agents endangered and framed, and one will accidentally kill an undercover detective who may not have been armed. But the explosive two-part season finale will finally shed light on Gibbs' painful history and help explain why he is who is he today. --Jae-Ha Kim

Season Four

The fourth season of NCIS begins with one of the investigators being charged with assassinating an Iranian prisoner. Former Mossad intelligence agent Ziva David (Cote de Pablo), who was introduced last season, has been framed, and there's only one man who can clear her name. Unfortunately, lead investigator Jethro Gibbs (Mark Harmon) has retired to Mexico. But since Harmon is the star of the show, Gibbs returns to the United States to help out his colleague. While most of his former team is happy, Tony DiNozzo (Michael Weatherly) has mixed feelings (During Gibbs' absence, DiNozzo became the de facto head of the team, and going back to being Gibbs' underling doesn't sit well with the usually easygoing special agent.). Like William Petersen on CSI, Harmon is instrumental to the success of NCIS. Low-key and sarcastic, he injects humor and drama into a role that could've come off as dull. And while other cast members may come and go, his presence makes even some of the weaker storylines forgivable. In general, this season--which originally aired from 2006 to 2007--is full of well-developed plot lines that drive each episode along at a good pace. But there are some subplots that are trite: When agent Timothy McGee (Sean Murray) reveals that that book he's writing is based on his co-workers, it's not much of a reveal. Also, the serial-killer storyline in this season overstays its welcome by at least one episode. As NCIS director Jennifer Shepard, Lauren Holly makes a sometimes unlikable character come to life, especially when Shepard's motives are questionable. As the show's name suggests, the majority of crimes featured revolve around military personnel, but some of the show's best moments occur when they touch of the personal relationships between the characters. All 24 episodes are included in this six-disc box set, which also includes commentaries, a Q&A session with cast members answer fans' questions, and a surprisingly interesting look at the props used on the show. --Jae-Ha Kim

Season Five

Describing season four of NCIS as "the season of secrets," executive producer Shane Brennan suggests that season five (offered here with 18 episodes, including a two-part finale, on five discs) is "the season of answers." For the most part, that’s true--but at season’s end, loyal viewers are likely to be thrown for a loop by the death of a major character and a startling set of changes bound to have a profound effect on the show’s future. Picking up where the previous year left off, this new batch jumps right in with a continuation of Special Agent Jethro Gibbs (Mark Harmon) and company’s pursuit of notorious international arms dealer La Grenouille ("The Frog," played by Armand Assante), whom NCIS director Jenny Shepard (Lauren Holly) is particularly keen on taking down--a quest that’s complicated by the fact that the bad guy is a CIA asset, and by Agent Anthony DiNozzo’s (Michael Weatherly) love affair with La Grenouille’s daughter. That st