Gibbs and Vance butt heads often as it is. Now that there's a family member involved, will tensions between the director and his top special agent boil over? Where do the shot-caller's allegiances lie?

In a clip from tonight's all-new episode of NCIS, Vance finds himself in a very difficult position as his brother-in-law - his wife's brother - is brought in for questioning in the murder of a Navy officer.

Vance acknowledges that Gibbs is his best agent, and seems to hedge when asked if he believes in the innocence of the unlikely suspect. Will he ultimately be exonerated? What will the fallout be?

Check out the sneak peek from "The Good Son" below ...

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