NCIS “Knockout” Season 6 Episode 18 March 15, 2009 NCIS Watch a sneak peek of NCIS Season 6 Episode 18 “Knockout” airing this Tuesday March 17 at 8pm on CBS. Also catch any NCIS Episodes you may have missed. (NCIS Episodes) You can also watch a preview from NCIS “Knockout” below and read all our NCIS coverage. Episode Synopsis: NCIS “Knockout” Season 6 Episode 18 – A boxer’s death leads Vance to start up his own investigation, causing a sparring match with Gibbs, on NCIS, Tuesday, March 17 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Google+ (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Pocket (Opens in new window)