An NCIS case changes from accidental death to murder when evidence reveals that a Navy lieutenant died of forced over-hydration. Meanwhile, Gibbs meets Ducky's new love interest.

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.