The discovery of two tiny corpses buried in the middle of London's toney Callander Square sees Inspector Thomas Pitt sent in to investigate; at first without his knowledge and then with his consent, his high-born wife Charlotte and her elder sister Emily, who's married for aristocratic prestige, help his inquiries by ingratiating themselves among Callander Square's worthies -- or, as it too often proves, unworthies. As the tale proceeds, more and more dirty laundry comes spilling out. It seems the case is going nowhere, though, until Charlotte and Emily (do they have a sister called Anne and a brother called Branwell?) discover a long-ago murder and a very recent one . . .
The bulk of the tale is, alas, devoted to one or other of our three detectives visiting people, having conversations that seem to contain very little information among a great deal of verbiage, and then leaving to have similar conversations with the next person they visit. Also given quite a lot of screentime, as it were, is one of Callander Square's residents, the reprobate banker, Reggie, whose hobby is bedding his parlourmaids; he's unfortunately such a stereotype of the knuckleheaded aristocrat that it's hard to take him seriously as an actual character, and I for one very rapidly tired of his company. By contrast, the three central characters worked quite well, as do General and Lady Augusta Balantyne, two of the seemingly stuffier Callander Square residents who turn out both, in their separate ways, to be quite admirable.
The edition I read has one of those godawful reader guides at the back (here called a Dossier); both in it and in one of the review quotes cited on the cover there's rapturous praise for Perry's evocation of Victorian London. It's actually in this that I felt the novel very grievously fell down. I got very little sense of place from the narrative. There were moments when I felt it suddenly engaged with its environment, as when the two sisters investigate a bedraggled, long-neglected garden, but for the most part I gained no sense at all of where we all were.
I picked Callander Square up at the same time as I did a much later entry in the series, Treason at Lisson Grove, and after finishing this one was disinclined to bother with the other. However, it looks as if in the later book Perry has expanded her scope a fair deal, so I'll certainly give it a try.
This is by no means a bad book. It just seemed to me that its aspirations were woefully limited; there was the sense of a very able author being unwilling to flex her muscles.