Warning: This story contains spoilers from Monday’s episode of “NCIS”.

Mark Harmon‘s time on Global’s “NCIS” has come to an end.

On Monday’s episode of Global’s’ long-running procedural, the longtime star has exited the series after more than 18 seasons. Harmon’s reduced presence and potential exit had been speculated ever since the drama was picked up for a 19th season.

How did “NCIS” write him out? With Harmon’s Leroy Jethro Gibbs no longer with a warrant out for his arrest, the former NCIS head technically could return to work. But, as NCIS Director Leon Vance (Rocky Carroll) revealed to Nick Torres (Wilmer Valderrama) and Jessica Knight (Katrina Law), he simply could not convince Gibbs to take back his badge. “He doesn’t want it,” Vance simply said.

Meanwhile, Gibbs broke the news to Timothy McGee (Sean Murray) — while out on a fishing trip at the lake — that he wasn’t coming back. “I’m not going back there,” Gibbs told McGee as he continued to fish. “To work?” McGee asked. “That too. I’m not going back home,” Gibbs replied, acknowledging that he’s “not sure” how long he’s going to be gone. When McGee started to panic and tell his mentor that they’re “50 miles from anyone or anything,” Gibbs simply said, “Not a bad thing.”

“My gut’s telling me, I’ll know when I find it,” Gibbs answered. “This sense of peace, I have not had this since Shannon and Kelly died and I’m not ready to let it go.” When it became clear to McGee that his old boss was set on beginning a new chapter, Gibbs offered his mentee the reins. “I could not have hoped for anyone better to watch my back for the past 18 years than you,” he said, pulling him into an emotional hug.

“Promise me you’re going to be OK,” McGee said, tears in his eyes. “I already am,” Gibbs promised as the two parted ways for good.

With Monday’s installment marking Harmon’s departure from NCIS, the franchise turns over a new leaf. But the door was left open for a potential return down the line.

“As an executive producer and dear friend, Mark continues to be an integral part of the fabric of the show. Our north star has always been staying true to our characters, and that truth has always guided the stories we tell and where those characters go,” executive producer and showrunner Steven D. Binder said in a statement. “So regarding the future of Gibbs, as longtime fans of the show may have noticed over the years… never count Leroy Jethro Gibbs out.”

The series also stars Brian Dietzen, Diona Reasonover, David McCallum and Gary Cole.

“NCIS” airs Mondays at 9 p.m. ET/PT on Global. For more, watch below.

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