WARNING: The following contains spoilers for NCIS Season 19, Episode 4, “The Great Wide Open,” which aired Monday October 11th on CBS.

Ever since last season, it’s been no secret that Mark Harmon’s time as Gibbs was drawing to a close. At first, it looked like he might just walk away from his job at NCIS and remain on the show. However, it soon became clear that his suspension and "Rule 91" were the beginning of the end because Harmon was being written off at his own request. Now, in “The Great Wide Open,” Harmon seemingly made his last appearance as Gibbs.

NCIS’ current plot has been a multi-episode arc, stretching back into Season 18. Gibbs and his reporter friend Marcie were investigating a serial killer when Gibbs’ boat blew up, which ended last season on a cliffhanger. The first four episodes of Season 19 have been a whirlwind. McGee and the team helped Gibbs , find the serial killer, but he ended up being a contract killer connected to Sonova Industries, a large conglomerate company.

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At the end of last week’s episode, the killer blew himself up, but he left Gibbs with the words “Naktok Bay.” That ended up being the break in the case that connected all of the victims back to Sonova. In this week’s episode, Gibbs and McGee flew to Alaska to find Sonova’s CEO, Sonia Eberhart. They found her, figured out how she covered up an environmental harm report and discovered that she found someone to hire the killer. Thus, Gibbs’ serial killer plot came to a close, but that wasn’t the only thing that ended with the episode.

Right at the end, McGee and Gibbs were fly-fishing when their plane arrived. McGee loaded up, but Gibbs never moved. It took McGee a while to get the picture, but Gibbs finally came out and said it. He wasn’t going back – to NCIS or even DC. He was going to stay in Alaska.

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NCIS Gibbs last episode

Early in the episode Gibbs told Ducky “lately I’ve been searching. I don’t know what I’m looking for.” Well, it seemed that he finally found it there, fishing. He explained that he was feeling a peace that he hadn’t felt since before Shannon and Kelly died, and he didn’t want to give that feeling up. McGee couldn’t believe that was the end, but he understood and respected Gibbs’ decision. So, after a tearful goodbye, he left Gibbs fishing all alone and at peace with his decision to walk away. Maybe Rule # 11 was the most important rule of them all: “When the job is done, walk away,” and that’s exactly what Gibbs did. The episode’s closing image was of Gibbs smiling like he hadn’t done in a long time.

The episode did leave the slightest chance of some small cameos for the rest of the season. Before he left DC, Vance gave Gibbs a satellite phone. So, he could theoretically call people on occasion. Realistically, however, Gibbs was written off to the fullest extent. His staying in Alaska will make it near impossible for him to actually appear on the show ever again.

To see out how McGee and his NCIS team officially move on without Gibbs, watch CBS’ NCIS on Monday nights at 9 pm. ET.

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