After discovering the Secretary of the Navy was bugged during a confidential briefing, NSA Analyst Eleanor "Ellie" Bishop, who predicted the security breach in exact detail two years ago, partners with the NCIS team on the case.

After a mysterious illness strikes children from military families, Gibbs and the team investigate the cause. Meanwhile, Abby and Jimmy partner with the Naval Medical Research Center to determine the strain of illness, all in hopes of delivering a cure before the holidays. Also, Director Vance struggles with forgiveness as his estranged father-in-law makes a surprise visit to his home.