'NCIS': Why the Show Isn't Airing Tonight and When It Will Return On 2/16/21 at 10:03 AM EST NCIS Season 18 may have only been airing for around a month in 2021, but the show is already set to take another break. Season 18, Episode 8, titled "True Believer," is set to be the final episode featuring Maria Bello as Jack Sloane, but CBS viewers will have to wait a while before they get to say goodbye to the character. Why It is usual for NCIS, and other shows on network TV to take breaks throughout the year. A TV season lasts about 40 weeks from September to May, while seasons of shows are at most 24 episodes long. Though shows try to burn through some of this by taking an extended break over Christmas, this still means that shows have to take weeks off now and then.