This British television movie is based on the true story of Caroline Meagher (Helen Baxendale), who served in the Royal Military Police from 1978 to 1990. As a Special Investigator, she finds herself uncomfortably assigned to root out lesbians in the British Army. Gossip and hunches lead to searches of letters, diaries, photos, underwear drawers and more. Humiliating interrogations follow from her male colleagues, destroying careers and invading the privacy of women they wish to remove from the force.

Caroline becomes more upset after her good friend Chrissie (Katrina Levon) comes out to her. When the two become lovers, Caroline is well aware of the secrecy that they must keep up if not to become victims themselves. The lesbian hunter is now a lesbian herself.

Our investigator is eventually given new duties and meets Louise (Laura Fraser, Iron Jawed Angels, Nina's Heavenly Delights) in Edinburgh. The two are in love when Caroline is posted to Northern Ireland, and although she knows the risks, she can't bring herself to destroy Louise's letters.

Finally, Caroline becomes a target herself. After four days of interrogation and twelve years of service, Caroline is discharged from the army. The real Caroline Meagher appears at the end of the film to point how bizarre the army's obsession with her sexuality seemed in the midst of the dangers of serving in Northern Ireland at the time.