Miss Seeton is that quintessentially British maiden auntie type, the sweet little old lady who thinks the best of everyone but nonetheless has some very firm opinions about things such as manners and discretion, with the end result that she manages to end up as the center of criminal storms. But as she thinks of herself as a lady and no lady would end up in the extraordinary situations in which she finds herself, she manages to forget the ruckus that is kicked up and wonders why anyone in the world would be interested in her.
Naturally enough, most of Scotland Yard think she's putting on an act, and just happens to be a modest investigative genius. Those policemen closest to her think she's a catalyst, and possibly psychic, or at the very least extremely perceptive to character. Her neighbors think she's a witch. It all makes for very entertaining and completely implausible reading— and it's written in that detached way that makes you forget how many bodies have piled up by the end, many of them people trying to take out the gently dotty Miss Seeton.
In Picture Miss Seeton, we are introduced to the lady as she pokes a man in the back to stop what she thinks is a discourtesy but is actually a murder. The police who are assigned to guard her from the wrath of a man known for his vengeful nature find out that by following her, they turn up clue after clue after clue, leading to a ring of criminals bigger than they expected.
In Miss Seeton Draws the Line, a series of child murders is the subject. This is where the "psychic" angle starts to get played up, as some of Miss Seeton's drawings turn out to be prescient. It's also mentioned that her conscious, conventional style of drawing is rather mundane, but her "caricatures", which she derides as childish, are beautifully executed. Anyone who knows a bit about psychology can probably figure this one out, but that's not the point.
Witch Miss Seeton deals with two cults, one evangelical and one devilish, which may be linked. Scotland Yard hires Miss Seeton to infiltrate, which she does with her usual aplomb— that is, she hasn't the faintest idea of what's she's doing but her bizarre improvisations inevitably turn out to be the perfect thing. It is, of course, amusing to see theoretically grown people childishly handing over all of their worldly goods to cult leaders who claim to protect them, after deriding the gullibility of others.
Miss Seeton Sings has Miss Seeton travelling abroad, at the behest of Scotland Yard... and against the wishes of those officers who know her true nature. They underestimate her capacity for accidentally doing the perfect thing, and naturally publicity has been spread about her, so when she catches the wrong flight her movements panic the orginization into acting desperately and giving the European police exactly the breaks they're looking for.
Odds On Miss Seeton has the retired art teacher disguised as a gambler, attempting to gain evidence against a crooked operator. Naturally enough, she enrages him to the point of doing murder, and just as naturally all of the bad guys end up killing themselves off while attempting to do her in. Quite silly and most effective.