AceShowbiz -

In celebration of the imminent Halloween, "NCIS: Naval Criminal Investigative Service" employs a story revolving around the festivity. In "Code of Conduct", the NCIS team discover that a Marine known for his practical joke is found dead on the Halloween Eve. They think that the victim's pranks may contribute to ghoulish retribution. Also, Ziva tries to adjust to her new role on the team.

Unlike the original series, "NCIS: Los Angeles" will not pick up a ghostly storyline. Instead, the episode called "Killshot" follows the investigation of a United States citizen of North Korean descent murder. The secrets to classified software are thought to be lost until NCIS uncovers a suspect from Director Vance's past. Through the promo, it is revealed that Pauley Perrette aka Abby in "NCIS" will make a cameo.

The crossover had been revealed even before the shows began their new seasons. Executive Producer Shane Brennan said in July that Abby will have a "fun little cameo" in the spin-off to help the Los Angeles team to solve a case.

"Code of Conduct" and "Killshot" air on Tuesday, October 20 at 8/7c and 9/8c respectively.

• Code of Conduct

• Killshot