On the last NCIS: New Orleans, the team looked into the murder of several victims at a federal server farm. They learn thousands of files have been stolen by hackers but they are unaware of what was stolen. However, when scandalous e-mails and videos of Mayor Hamilton having an affair come to light, the team realizes they have to work hard to find the hackers.
Evidence leads them to their old friend Elvis, who informs them the hacking is the work of Ethan Beck, his protégé who learned about hacking from him. However, he never expected him to go as far as to hurt anyone. But when Ethan Beck himself is found dead, they realize something bigger is in the works.
Meanwhile, Sebastian begins his first case as a special agent. But considering the case at hand, emotions run high when the hackers send everyone e-mails that shed them in a bad light to their co-workers. Despite fighting with one another, the team works to catch their killer.