The second half of “NCIS” Season 13 returns with an explosive 2-part crossover with “NCIS: New Orleans.” The first promo video for the special episodes has finally been released. The series returns on Tuesday, Jan. 5. with episodes titled “Sister City: Part 1” and “Sister City: Part 2.”

Warning, this article contains spoilers for “NCIS” Season 13 and “NCIS: New Orleans” Season 2. Proceed at your own risk.

In the promo video shared by the official “NCIS” Twitter account, Abby Sciuto (Pauley Perrette) introduces her younger brother Luca (Tyler Ritter) to her colleague, Anthony DiNozzo (Michael Weatherly). The introduction is quite unconventional as Tony responds by arresting Luca.

As previously reported, Abby’s brother is wanted by the NICS, due to his connection to the lethal poisoning of the passengers and crew of a chartered flight from Washington D.C. to New Orleans. He is the chef who prepared the meals for the flight, which immediately puts him under suspicion.

Things get even worse for Luca, as the NCIS also discovers that he has had some involvement with a Russian assassin. Guest star Lev Gorn is also seen in the promo video, as he comes back to reprise his role as Russian Counselor Anton Pavlenko.

The “NCIS” team in Washington D.C. will work in close cooperation with Dwayne Pride’s (Scott Bacula) team in “NCIS: New Orleans.” In an agent swap, Sebastian (Rob Kerkovich) will fly to D.C. to help with the forensic evidence, while Bishop (Emily Wickersham) will drive down to New Orleans to deliver an important package.

Meanwhile, Abby will be faced with the tough decision on whether she should attempt to break her own brother during interrogation, or if she should let Special Agent Jethro Gibbs (Mark Harmon) do it for her.

“Sister City,” the “NCIS’ Season 13 and “NCIS New Orleans’ Season 2 crossover, will air on Jan 5. Part 1 will be at 8 pm and Part 2 will be at 9 pm ET on CBS.