A Navy Commander is blackmailed into killing herself after failing to go through with some unspecified act that the blackmailer had demanded.
It doesn't take the team long to figure out that there was more in play than a simple suicide.
Meanwhile, Bishop and Reeves continue to investigate into Chen, and Reeves finds one of Chen's couriers. This in turn leads them to an old radio tower.
Which, coincidentally (!) happens to be where the blackmailer had hacked the commander's television to threaten her family.
This revelas Bishop and Reeves's side investigation into Chen, earning them a rightful chewing-out at the hands of Vance. Congresswoman Flemming informs them that Chen is now working with the CIA, so they have to stand down.
Bishop figures out some of Chen's remaining code: it's a virus that exploits weaknesses in generators in electrical plants. She lures Chen to the radio tower and handcuffs him to a generator.
Instead of arresting him, she tells him that she has informed the Syrians he's working with that he's working with the CIA. She then leaves him with a copy of the virus, which he uses to blow himself up rather than wait for the Syrians.
Gibbs warns her that she is still going to pay the price for her actions.