While Mark Harmon's involvement on NCIS Season 19 remains a mystery, but at least we finally have some plot details.

CBS is finally lifting the lid on what fans can expect on NCIS Season 19 Episode 1, and, well, it's going to be a tough watch for longtime fans of the popular series.

"As the NCIS team searches for Gibbs after wreckage from his boat is discovered, they find out he was tracking a serial killer with journalist Marcie Warren (Pam Dawber), who wrote an exposé on him," the short and sweet synopsis reveals.

If you watch NCIS online, you know NCIS Season 18 Episode 16 showed the former leader's boat being blown to smithereens, but it looked like the beloved character made it to safety.

The highly-anticipated premiere is set to feature the following regular cast members according to CBS:

Mark Harmon (NCIS Special Agent Leroy Jethro Gibbs)

Sean Murray (NCIS Special Agent Timothy McGee)

Wilmer Valderrama (NCIS Special Agent Nicholas “Nick” Torres)

Brian Dietzen (Medical Examiner Jimmy Palmer)

Diona Reasonover (Forensic Scientist Kasie Hines)

Katrina Law (NCIS Special Agent Jessica Knight)

Rocky Carroll (NCIS Director Leon Vance)

Yes, that is Mark Harmon's name up there, so there's a good chance we'll be seeing the character in some capacity, which should be music to the ears of many fans.

David McCallum (Dr. Donald “Ducky” Mallard) is listed as a recurring player for the episode, so that's a good thing.

As for the guest cast, you can check it out below:

- Pam Dawber (Marcie Warren)

- Katherine Cortez (Thelma McKeever)

- Dave Florek (Virgil McKeever)

- Travis Hammer (Faux County Deputy Randall Sledge)

- Terryn Westbrook (County Deputy Regina Unger)

- Yenniffer Behrens (Marta Jimenez)

- Derek Chariton (Lonny)

- Allie Davis (Sandy)

- Colin Land (NCIS Special Agent Brent Hollister)

Yes, it's going to be a tense installment.

Harmon's long-term involvement with the series has been in question for several months now, stemming from reports that CBS was prepared to cancel the series if they couldn't lock the lead in for more episodes.