Harm goes undercover as a Marine gunnery sergeant to help Mac in her investigation of questionable Marine training methods and becomes a victim of unsafe maneuvers himself.

While undercover, Harm learns that the tough-as-nails officer in charge of Force Recon training, Capt. Koonan, introduces unexpected problems into the training missions as a means of teaching the men to react quickly to surprises during combat. In addition to testing the Marines' mettle, the method also doubles their chances of returning safely from combat. However, in the mission in which Harm is involved, the method backfires dramatically, leaving five men trapped in a training maneuver destined for a disaster that even Capt. Koonan can't reverse, and it's up to Harm to get the trainees -- and himself -- out safely.

Bud has his hands full when his obnoxious and abusive father, Big Bud, and his younger brother, Mikey, arrive in town for his wedding. Big Bud throws a stag party at a boisterous strip club where Harm's dress whites end up on the body of a stripper. A fight breaks out and Harm, Bud and Chegwidden find themselves in the slammer on the day of the wedding.

While Mac goes downtown to bail them out, Harriet begins to have second thoughts about the imminent nuptials.