When a teenage pyromaniac terrorizes a neighborhood, the police are helpless as frightened victims refuse to testify against him. Enter Hetty, posing as the Irish sister-in-law of one of the residents. Her plan: infiltrate the local sewing circle and get the lowdown on Lenny the firebug and his gang.

A military wife hires Hetty when a mysterious photographer starts stalking the woman's daughter and her fiancÃ. Tipped that an Australian is involved, Hetty and Geoffrey go undercover as ""Aussies."" They track down the mastermind and learn more than their client wants to know.

Called to investigate a string of robberies targeting Indian restaurant owners, Hetty herself is mugged! The plot thickens when Robert is the unwitting receiver of stolen goods. As Hetty delves deeper into the activities of the masked bandits, Geoffrey, sporting a stunning new hair-do, rides shotgun for her protection.

Hetty seeks compensation for the victim of a road rage incident in which a female driver hit another in the face.

Hetty looks into a case of bullying when her great nephew is suspended from school, after someone plants an Ecstasy tablet in his blazer.

Hetty represents a neighbour at a creditors' meeting and her agency is asked to find a missing company director and his money.

During a quiet hospital stay for surgery, Hetty uncovers a robbery ring run by nurses and helps clear D.C.I. Adams in a sexual assault frame-up. Meanwhile, Hetty's brother-in-law, Frank, gets mixed up with a lusty widow.

Hetty is approached by Hansi, a German gentleman whose golden years have been hampered by a painstaking search for his sister, whom he lost contact with during World War II. However, Hetty passes the case off to Geoffrey and Janet, when it comes to light that this is not the only pain Hansi has been suffering. Someone at his retirement community has been making pointed references to Nazism at Hansi, something he had never been a part of. The person is going so far as to deface Hansi's garden in the shape of a Swastika. Hetty goes undercover as a potential tenant of the retirement community, where she comes into contact with characters that seem to come right out of the mystery novel she's reading: a regimental romantic, a frail woman who has remained alone since her fiance's death in the war, among others. All seem to have motives for harming Hansi. Geoffrey and Janet find Hansi's nephew, only to find that he is ashamed of his uncle's German heritage and prefers to continue hiding. Mea

A clock aficionado suspects he's been handed stolen goods when two thugs bring him a valuable antique timepiece for repair. Meanwhile, Frank and Janet break Hetty's number-one rule by getting mixed up in a marital dispute. Oddly enough, the two cases turn out to be linked.

Helga Allowby, a self-described spinster, has been accused of sending noxious poison pen letters to the residents of her village–and she wants Hetty to prove her innocence. Hoping to penetrate the mistrust that pervades the village, Hetty goes undercover as Tara Hall, a visiting painter. When Hetty turns up next on the mailing list, she suspects that Miss Allowby is guilty of bad penmanship.

Hetty is called in to investigate when one by one, the contestants in the Blainthorp Muiscal Festival lose their voices. The sponsor of the festival, Oliver Hardiman wants the mystery solved but Hetty only has five days.She finds herself caught up in a battle between rival pharmacists who may be using their skills to harm the finalists.

Hetty is called in by the Mayor of Titterslow to look for his daughter who has runaway. She has learning difficulties and the Mayor and his wife want the matter of her disappearance to be kept very quiet. Hetty discovers that she left with her boyfriend, Bernard, who also has learning difficulties and that they were making their way to a country hotel.

Hetty gets mystical as she investigates Maurika Rome, a spiritualist suspected of using séances and blackmail to prey on the savings of the recently widowed. When Hetty goes undercover and invents a late husband she wishes to contact, she begins to wonder if Mrs. Rome isn't the real thing - until a woman claiming to be her "late husband's" illegitimate daughter shows up demanding money. Geoffrey's secret romance with Rome's daughter, Sara, threatens to undermine Hetty's carefully laid trap and nearly causes him to quit the agency.

The children of well-to-do widow Gillian Snape are worried that her photographer-fiancé Lester Rose is marrying her for her money, and hire Hetty to investigate Rose's past. With Geoffrey's help, Hetty learns that Rose is a gambler and a gigolo with several previous identities. Surprising facts revealed by two women from his past and Hetty's tense undercover visit to his studio expose a somewhat less thorny side of the man. Still, is he the marrying kind?

Hetty goes undercover to a women's shelter in a confidential location - and where no man may enter. Detective Chief Inspector Adams suspects that the shelter's security has been severely compromised by an inside informer. Hetty's quest to find the leak opens her eyes to the terrifying realities of spousal abuse, and results in a gripping conclusion as she leads the women in defending their sanctuary against a violent motorcycle gang.

Hetty Waintthropp is annoyed at the cards celebrating her sixtieth birthday--they all offer her well wishes for ""joining the club"" of senior citizens and old-age pensioners, even though she's not entitled to a pension. Determined to make something of herself, Hetty gets a job at the local post office, where she proves her mettle quite quickly by throwing out a troublemaking biker and chasing down a shoplifter.

Hetty is called on by a pair of worried parents whose deaf-mute son, Malcolm, has disappeared while out bird-watching on the day he was to meet his mail-order bride from Thailand.

A restaurant owner in Italy is sent a package apparently containing his son's index finger plus a photo of him in front of graffiti art in Manchester and a warning: Silence and await instruction. The distraught family finds solace when who should be taking a holiday in Italy than Hetty Wainthropp? After snooping at her passport and learning she's a detective, they come to her and she accepts their case. As Hetty investigates, she discovers that Gianni may be involved in a bad loan connected to the mafia.

Hetty and Robert travel to the small village of Readsby, where his revered elderly uncle, a former professional soccer player, has apparently committed suicide. But Hetty doesn't believe it -- for one thing, where's the suicide note? And when she begins to suspect that the villagers of Readsby, once a notorious haven for witches, are engaged in satanic practices, she's determined to prove that they were somehow involved -- with surprising results!

A desperate Hetty takes Geoffrey up and down the streets and sidewalks of town advertising the detective agency. This proves to be a wise method of business, as they pick up a client: a woman whose estranged son, who has been diagnosed with schizophrenia, has disappeared from his sheltered housing unit. As Hetty investigates, she discovers that the woman's son, Reg, has had a hard time being accepted by society, as well as his stepfather, who turns out to have been the person who threw Reg into the streets in the first place. As it becomes clear that Reg has gone off his medicine, Hetty finds herself in a race against the clock to try and find the man before he hurts himself or others in his delusional state.

An old friend of Hetty's - her partner in a music-hall routine years ago -- seeks her help in locating her troubled foster daughter, Chrissie. A teenage mother, Chrissie has disappeared just as a series of arson attacks on local homes have occurred --and Chrissie has a history of setting fires! As Hetty and Geoffrey look for Chrissie, a local newspaper photo competition reveals more than the photographer intended, prompting Geoff to dress in drag -- blonde wig, high heels and all -- to confront the arsonist. Hetty picks up a much-needed reward for her work in this case, and at the presentation of the check, proves that the new gumshoe hasn't lost her knack for the ol' soft-shoe!

During a visit to childhood friend Edith, retired housewife Hetty Wainthropp discovers that her husband, Frank, has a son by a previous marriage. Hetty decides to turn amateur detective to trace him. When this gives her a taste for detection, Hetty decides to set up a private detective agency.