NCIS season 18 episode 3 is an installment that takes place right after the events that happened in the 400th episode of the police procedural drama. While some of the remaining stories will still be covered, it will see the team taking on a new case, where they'll be going on treasuring hunting.

NCIS season 18 episode 3 carries the title "Blood and Treasure." The team found two dead bodies in the forest and they're going to investigate the circumstances behind their deaths. Later on, the case leads them into the "wild world of modern-day treasure hunting."

The team must locate the treasure as this could be the answer in pinning the killer's location. The treasure map, however, was swallowed by one of the victims. They need to obtain it as soon as they can before the culprit could run away.

But, it looks like they're not in an entirely better condition while doing the investigation. In the sneak peek of NCIS season 18 episode 3, Leroy Jethro Gibbs (Mark Harmon) went to a bar to meet some of the agents, where they celebrate Timothy McGee's (Sean Murray) milestone.

Most of the team members are feeling the hangover after the celebration. Gibbs had a lot of drinks, as well as Ellie Bishop (Emily Wickersham). As shown in the clip, the latter is working out in the field while wearing sunglasses. Also, Nick Torres (Wilmer Valderrama) has had his own problem after that night.

He didn't drink anything during the celebration and wasn't feeling the hangover. Food poisoning was his biggest problem after eating a "not-so-fresh" tuna. Despite feeling the aftermath of the celebration, they are still working out in the field to solve the case-of-the-week.

Meanwhile, a Back to the Future alum is set to guest star in NCIS season 18 episode 3. Tom Wilson will be playing the role of Abgus Demint, someone who's handling the treasure hunting operation within the area where the murder took place.

He believes that no treasure hunters would be involved in something like this. Yet, one of the questions is whether or not he knows what happened and just covering things up. The team will be investigating all the angles to solve the crime.

As for what else is coming, Gibbs and Tobias Fornell (Joe Spano) will continue with their investigation in finding the opioid kingpin. They already had conversations about this matter, which is something connected to what happened to the latter's daughter.

NCIS season 18 episode 3 will be airing on Tuesday, Dec. 8, on CBS.