To take another mystery series that I read from the library: Laurie R. King’s The God of the Hive is the direct sequel to The Language of Bees. Alas, I cannot recommend it.
This book entirely abandons the device of the novels as Mary’s manuscripts, making instead her POV one of many, and then plays ridiculously transparent and manipulative tricks with the multiple POVs. It introduces a character that I find very troublesome when it comes to problematic stereotypes. And it seems to be an entirely different story than its prequel, and a less interesting one at that.
I’m not sure I’m going to buy either of these, now.
I think I would have been just as happy to have the series end with Locked Rooms.
I think the series may be getting constraining on the author, which is fine, but one doesn’t have to break constraints in an annoying way.