After Gibbs' return, a major subplot involved the friction between him and Ducky. Ducky was deeply hurt that Gibbs hadn't told him about Shannon and Kelly before his "retirement". Their eventually "making up" in the morgue remains one of the show's most poignant moments.
The season kicks off with the team in total disarray. Following Gibbs' sudden retirement to Mexico at the end of Season 3, steps up as team leader. This brief period wasn’t just a "fill-in" arc; it showcased Tony’s untapped maturity and proved the team could function—barely—without their stoic boss. 2. Character Arcs That Stuck the Landing
A finale that leaves Tony and his girlfriend Jeanne captive and several major secrets finally unraveling.
