Don't call it a finale: as with many TV shows, NCIS had its production cut short in early March as the coronavirus pandemic became more grave and required workplaces to close. As a result, NCIS — which was mere days away from shooting a historic 400th episode — only got up to filming Episode 20 of a planned 24, and that episode, "The Arizona," airs this Tuesday.

Acclaimed actor Christopher Lloyd guest stars in the story, playing a man named Joe Smith who sends the team into a tailspin when he claims to be a World War II veteran who was aboard the U.S.S. Arizona during the attack on Pearl Harbor in 1941. Most of the people on the team, however, have some serious doubts about his story. When it's revealed that the elderly man may have some mental health and memory loss issues, it becomes easy to brush Smith's claims off as faulty recollections of a senior citizen who's struggling. Easy for everyone except Gibbs (Mark Harmon), that is.

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"For Gibbs, it all connects back to his father, who was a World War II vet," said Gina Monreal, a co-executive producer on NCIS and a writer of the episode. "I think he sees his father [in Joe], and helping someone like his father is important to him; he has this initial connection, and he's able to understand." Where just about everyone else is convinced Joe Smith is mis-remembering or intentionally misleading the NCIS team, Gibbs keeps extending Joe more benefit of the doubt, even as clues against Joe mount and patience wears thin. Whether Gibbs' grace turns out to be warranted or not is a spoiler, but either way, the process opens Gibbs up emotionally in ways that aren't entirely characteristic.

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"At the end of this episode," Monreal told TV Guide, "he opens up to McGee about his past. He's seeing ramifications of the sacrifice he's made for the team and his family. You're seeing an emotional side to him." That's one of the main reasons why fans shouldn't consider this episode a season-ender: the vulnerability Gibbs begins to show in "The Arizona" will become a theme that'll continue as NCIS marches ahead post-coronavirus. "One thing about the Gibbs character," Monreal said, "he's constantly evolving."

Mark Harmon and Christopher Lloyd, NCISMark Harmon and Christopher Lloyd, NCIS

NCIS airs Tuesdays at 8/7c on CBS.