This series of atmospheric Gothic mysteries suffers from two main flaws.
The first, the weakness of the Victorian setting, was more annoying to me as it could easily have been improved by even minimal research. I mean really minimal, like using wikipedia to check whether an event had happened before or after the year the action takes place. The characters' speech and behavior was totally inauthentic -- a bunch of kids playing dress-up in frilly gowns while exclaiming "Cool!" and "Totally!" to one another.
The second problem was psychological shallowness. This wouldn't be as big a deal except that the story consists of a series of mysteries (can you still call them that when they are completely obvious to the "detective" as well as the reader?) which are motivated entirely by psychological issues that make no sense
. Maybe this is supposed to be Gothic? Everyone is just CRAZY! and that's why they do CRAZY shit liking running around London* in a bunny mask decapitating girls.
*Except that after being told there is a serial killer with this modus operandi, we see a girl murdered at a party and find out she is only the second victim. Pretty prescient of the police to catch on at victim one, eh?