A Navy hospital corpsman goes on trial for the murder of a Marine during a field exercise; Mac prosecutes, Harm defends, and Bud serves and argues on the jury but later has second thoughts. Sturgis helps a submarine family stay together.

Harm and Mac go to sea during wartime operations. Harm flies the next mission, hits the target, and draws enemy fire; his aircraft sustains damage, but he safely returns. Bud runs into trouble at work, and Sturgis becomes closer to Bobbi.