After NCIS finds a secret government bank account that's funding a nationwide network of vigilante justice, the team must determine who is acting as judge and jury.

Former FBI Agent Tobias Fornell pleads with Gibbs to do whatever is necessary to take down drug dealers and suppliers in the area after his daughter, Emily Fornell, is hospitalized from an opiate overdose. Gibbs is haunted by the personal aspects of the case and his history with vigilante justice.