The premise and characters derive from the 1986 novel Missing Persons by David Cook (who would co-write the BBC show). ITV had already made their own feature length adaptation of the novel, but opted out of a full series, with the BBC series choosing to rewrite its own origin pilot. The show ran for four series, and while the BBC commissioned a fifth, it never came to be.
Provides examples of:
- Abuse Mistake: Once, when Hetty fell down a staircase while walking in high heels and ending up with a black eye, D.C.I. Adams asked her to pose as a victim of spousal abuse and investigate a shelter for battered women; somehow the shelter's location was revealed to a few of the women's husbands, possibly resulting in at least one death.
- Always Murder: Often averted.
- Borrowed Catchphrase: Hetty likes to borrow Hercule Poirot's "little grey cells" catchphrase.
- Casting Gag: This isn't Patricia Routledge's first foray into the mystery genre, having voiced the mother of Lord Peter Wimsey in a number of BBC Radio adaptations.
- Embarrassing Cover Up: A client hires Robert and Geoffrey to find out if his fiancee is faithful; they bring in another man to approach her and see if she's willing to cheat. When he takes her out to a jazz club, Robert and Geoffrey keep watch, but this attracts her attention and she says they look familiar. The man tries to throw her off the scent by saying they're drug dealers.
- Fidelity Test: One of the B-plots involves Robert and Geoffrey, while Hetty's occupied with another case, approached by a man who wants them to set one of these up to test his girlfriend. As Robert's too old and Geoffrey's too young, they hire a third party to do so. It backfires when the girl not only falls for it, but dumps her boyfriend for the mark. Needless to say, the boyfriend isn't happy.
- Friend on the Force: D.C.I. Adams.
- Good Victims, Bad Victims: Discussed in one episode where Hetty goes undercover at a refuge for battered women. When she points out to an educated and "posh" resident that her background and schooling didn't save her from the abuse, the woman replies that it's not about that and victims, like abusers, can come from anywhere.
- Irregular Series: The pilot aired in 1990, whereas the four full series aired 1996-98.
- Karma Houdini: Not all of the criminals face charges for their crimes, typically due to lack of evidence. They will often face other consequences, though.
- Kitchen Sink Drama: Although a more light-hearted example than the usual, given the Oop North setting and the working class characters the series could almost be described as a Kitchen Sink version of Miss Marple.
- Little Old Lady Investigates: Hetty. A somewhat more realistic example than most, in that most of Hetty's cases were fairly small-scale in nature (or at least started off that way) and matters that the police were unlikely to be interested in. She was also a registered official private investigator.
- Magical Romani: Hetty investigates one who works as a medium. The woman turns out to be blackmailing her clients, although it's suggested she does have some real psychic powers.
- Maybe Magic, Maybe Mundane: One episode is based around Hetty investigating claims that a medium is blackmailing her clients. Hetty catches the woman out - but the medium did come out with many accurate details about Hetty's life and family.
- In another episode, Hetty investigates the possibility that the death of Robert's uncle is connected to practicing witches in the village where he lived. Most of the events of the episode have a mundane explanation (and his death turns out not to be connected to anything supernatural) although there is some suggestion that there really are active witches in the area.
- Mr. Fanservice: Dominic Monaghan, in his early twenties at the time, was very clearly intended as eye candy. Never is this more apparent than when he gets an utterly gratuitous Shower Scene complete with rear nudity in one episode.
- My Beloved Smother: Geoffrey has one, who in one episode comes to visit and begs him to move back in with her whilst Hetty and Robert are away.
- Never Suicide: Robert's elderly uncle seemingly commits suicide, but Hetty and Robert suspect it could be murder and investigate. Averted with the discovery he really did commit suicide. He'd discovered his carer was stealing from him, including his beloved football medals; but he feared that if he said anything, no one would believe him and he'd be sent to a nursing home, so he killed himself out of sheer desperation.
- Not What It Looks Like: Hetty visits a village with a history of witch trials, and walks in on what she thinks is a coven of Satanists preparing to sacrifice a goat and a child. They're actually making an amateur film in order to encourage tourism to the village.
- Ooh, Me Accent's Slipping: When Hetty goes to stay with a client to investigate her current case, the client says Hetty is her Irish sister-in-law. Hetty can't do an Irish accent well and just tries to keep as quiet as possible so she doesn't give herself away.
- Oop North: The series was set in Lancashire.
- Private Detective: Unlike most little old ladies who solve crimes, Hetty actually is a registered private detective.
- Surprisingly Realistic Outcome: Into the Little Old Lady Investigates genre; Hetty is a registered private investigator who actively stays away from major cases that are the police's jurisdiction, and tends to focus on smaller-scale incidents.
- Straw Misogynist: In one episode, a woman is killed by a car as she runs away from her violent husband, who had tracked her down to a women's refuge in another town. As Hetty goes undercover at the refuge to find out if someone who lived there could have leaked the address, Geoffrey investigates the deceased woman's husband. He fits this trope completely and lectures Geoffrey about how women need to be beaten to keep them in line.
