Episode 70 of "JAG"
s04e09 People v. Mac

Mac is arrested and placed on trial for a major felony, along with her former commanding officer and mentor, Col. John Farrow. Conviction could result in long prison terms. Harm volunteers to defend her, but his efforts are thwarted by Farrow's defense attorney, JAG exchange officer, Australian Navy Commander Mic Brumby. Harm feels that neither defendant has come clean with the truth and he begins to search for evidence which is not forthcoming from either one. Ultimately, he learns that Mac and Farrow have each been trying to protect the other. The key witness in the case turns out to be a major surprise to both defendants.