Among everyone in Gibbs' (Mark Harmon) NCIS team, McGee (Sean Murray) and Bishop (Emily Wickersham) are the closest. The two have shared a close friendship on the show so far, and if the promo for episode 3 indicates anything, it will be the test of their friendship.

In episode 3, titled "Incognito", "A marine is murdered at Quantico hours after calling Gibbs to discuss a possible case. Bishop and McGee go undercover as a married couple to run surveillance on a marine lieutenant and his wife," reports TV Guide.

The promo for episode 3 reveals an intimate moment between Bishop and McGee. The two share a kiss and it remains to be seen if it is just a part of their role play.

Furthermore, the preview clip that finally spills romance into season 13 also hints that the undercover assignment goes horribly wrong. Things go awry when Bishop enters the lieutenant's house without her partner and assistance and perhaps gets kidnapped.

At one point in the clip, Gibbs breaks into the suspect's house with his gun.

Showrunner Gary Glasberg said in an interview to TV Line that episode 3, which depicts McGee and Bishop as a married couple, is a lot of fun.

Furthermore, Glasberg added that cast members McGee and Bishop's personal journeys will be documented in this season. While McGee will become a mature agent, Bishop's personal life will affect her and change who she is as an agent as well, he said.

"NCIS" season 13 episode 3 airs on Tuesday, 6 October, at 8 pm EDT on CBS. You can watch the episode online via CBS Live.

Watch the trailer here: