Harm and Mac investigate an apparent murder aboard a ship at sea; while Harm interviews the prime suspect inside the brig, the ship collides with an uncharted reef; in the brig the lights go off, the telephone dies, the compartment starts to fill with water, and the suspect goes berserk. Circumstances change in the brig, and Harm gives consideration to an alternate theory. The Chief Master at Arms abandons Harm and the sailor. The admiral, after a retirement party, arrives aboard a nearby ship, which has come to help; he lends a hand, and Harm and the suspect figure things out. The admiral starts to wonder about the degradation of skills while one ages.
—DocRushing