Set in the same universe as The Watchmaker of Filigree Street, this book is not a sequel although one of the main characters from the previous books makes a couple of quite lengthy appearances - while that book was set in London, The Bedlam Stacks takes place mostly in Peru, as our protagonist is part of a mission sent to try and steal cuttings from cinchona trees in order to help produce quinine for the East India Company.
We first meet Merrick Tremayne when he's recovering from a serious injury at his family home in Cornwall, which is literally falling apart around his ears. Against his better judgement, he agrees to take part in an expedition to Peru and follow in the footsteps of his father and grandfather. With Merrick and his companions, we spend a lot of time travelling and eventually arrive at New Bedlam, in the company of its priest, the taciturn Raphael. The village itself is on the border of a mysterious forest, the shortest route to the cinchona but also both the village and the forest are guarded by the markayuq (who Merrick mistakenly believes are clockwork).
Anyway, matters come to a head, Merrick and Raphael end up travelling into the forest regardless and Merrick subsequently discovers there is much more going on in darkest Peru than just the cinchona. In a flashback sequence, we discover that Merrick's injury was deliberately engineered by a much-younger Keita in the hope that it would stop him going into the forest, so I wouldn't be surprised at all if the aftermath of all Merrick's actions comes back to have significant consequences in a future novel.
Unlike both of the main characters in The Watchmaker of Filigree Street, I found it difficult to empathise with Merrick - he comes across as quite weak and frightened of social consequences a lot of the time, even when he is doing things he knows are morally reprehensible. Raphael is a more interesting character, facing his own immortality in many ways, but he still didn't quite work for me either. As a result, while I'd said in my previous review that I felt it was unlikely I'll re-read The Watchmaker of Filigree Street, in hindsight I think I was wrong about that just on the basis of the relationship in it between Thaniel and Mori and it's probably The Bedlam Stacks I won't want to re-read.
I'm still looking forward to seeing what Natasha Pulley writes next, but it'd be nice to see her write about women too. Grace Carrow got fairly short shrift in the previous book and women are very much supporting characters here too, either devoted wife to Merrick's fellow explorer or helpful villager and that's just about it.