When a petty officer is found dead and Vance's brother-in-law, Michael Thomas, becomes a murder suspect, Vance puts pressure on Gibbs to prove his innocence. Meanwhile, Tony is disgruntled by a negative performance review and is determined to prove it wrong by being less chatty in the field...however unlikely a mission. At first the murder case looks to have clear motive when NCIS discover the officer's best friend was sleeping with the officer's girlfriend. But when the team uncovers an underground gambling ring that the officer lost all his money at and which Thomas was a part of, they're able to link the murder back to him: the two got in a fight and Thomas accidentally killed him. Thomas begs Vance to help him out, but the director realizes he can't save him this time; however guilty he feels for letting his brother-in-law down, sometimes you have to let people go.