'NCIS' Season 18: Why a New Episode Didn't Air This Week On 4/21/21 at 6:48 AM EDT NCIS Season 18 was meant to continue on CBS on Tuesday, April 20 with "Sangre," the first episode since Gibbs (played by Mark Harmon) spilled the details of his suspension to a journalist. Real journalism got in the way of the episode airing, however, with Episode 12 of the show's season postponed by the network. Why On April 20, CBS preempted their prime-time line-up, meaning that the planned episodes of NCIS, FBI and NCIS and Most Wanted was replaced by the CBS News special The Chauvin Verdict. CBS came to its decision to change its scheduled programming after the jury returned with a guilty verdict in the Derek Chauvin trial just hours before the episodes were due to air.