The team's investigation into the electrocution of a college student working on a classified Navy project leads them to his inquisitive daughter, who may be the key to accessing his work.

After Callen’s father, Garrison is found in an NCIS patient’s hospital room during a radiation poisoning case, Callen must take him to the boatshed for interrogation. Also, the team discusses their Thanksgiving plans.

After an unknown female assailant kills two men disguised as Sherriff’s deputies in front of Callen’s home, the NCIS team gets a new lead in the ongoing mole investigation. Also, Nell visits a prison to interview an inmate withholding information on the department’s leak.

Hetty goes rogue, leaving the NCIS team completely in the dark, and the mole kidnaps one of the agents.

As the team races to save Kensi from Ferris/Sullivan, they find themselves questioning who they can trust when old faces resurface.