Gibbs is worried about Tony's ability to handle his job when Tony's father turns out to be linked to their newest investigation, an assassination attempt on a foreign prince.

The team is surprised when Gibbs asks Tony's father to join them in a murder investigation.

After Anthony DiNozzo, Sr. is found in a car with a dead body in the trunk and no memory of the previous night, the NCIS team must figure out if he is capable of murder. Meanwhile, Tony is sidelined for this case and must go against orders to try and prove his father’s innocence.

Someone winds up dead when DiNozzo confronts a man impersonating a Navy officer; DiNozzo's father needs to share a secret with his son.

A Navy Public Affairs officer is murdered, and the victim's wife and mistress accuse each other of the crime. Meanwhile, Anthony DiNozzo Sr. helps a homeless woman who believes he is her father.

NCIS, FBI and MI6 continue an international manhunt for an escaped British spy who is targeting current and former agents.

Jimmy is torn between family and work after his father-in-law, Ed, asks him to tamper with evidence from NCIS’ current murder investigation. Also, Ed’s poker buddy, Anthony DiNozzo, Sr., offers to help with the case.