Callen's murky past will present the agent with a serious dilemma during the NCIS: Los Angeles season 6 finale.

The title of "Chernoff, K" signals that episode 24 will be highly revealing, following the precedent set by "Callen, G," "Hetty, L," and "Blye, K." Like last year's "Reznikov, N," the identity of the title character is currently a mystery, but there is little doubt that the mysterious Chernoff will be connected to Callen's (Chris O'Donnell) father.

"There's a fairly big reveal at the end," executive producer R. Scott Gemmill informed TV Guide. "Callen's put in somewhat a precarious position because he has an opportunity to learn more about his past, but he has to focus on the task at hand more. So, he's sort of torn between the two opportunities."

The task at hand will involve that mysterious oil tanker that went missing during "Beacon." As the team travels to Moscow to close the case, TV Guide promises that both Hetty (Linda Hunt) and Arkady Kolcheck (Vyto Ruginis) will have a few shocking reveals up their sleeves.

Find out more when NCIS: LA airs Mondays at 10 p.m. ET on CBS. Click the video below to see a preview for next week's episode, "Field of Fire."

Tags: NCIS: LA NCIS: Los Angeles television CBS