Jeffrey De Serrano

While investigating a serial bomber's attack on a small town, Gideon learns that the perpetrator is a protégé of his nemesis, who had murdered his previous team of profilers.

Sam fears for his family's safety when his wife is called to resume a former CIA cover after a case suggests ties to the infamous Sidorov and his stolen nukes.

Callen takes on a secret project, leaving the team in the dark; when Hetty shuts down Callen's operation, the team must locate him before he gets in trouble.

The team are left scrambling for answers when the mole compromises the NCIS. Planted evidence leads to Callen, Sam, Granger and Deeks's arrests.

The fallout from the nuclear blast in Denver will hit Jericho in an hour and Jake has to get the residents inside. The official shelter is not adequate and Jake must find another shelter to protect them.

Walt teams up with Lucian Connally (recurring guest star PETER WELLER) to narrow the field of suspects in the aftermath of his wife's murder. And while the team tries to track down a witness who could help Henry's case, Branch's behavior causes trouble.