I bought this for the kid a while back. I *certainly* didn't want to read it. One of my least favorite novels of all time was a Holmes knock off. Lucky for me, this year I've been trying to catch up on books that have been languishing unread on my shelves (vs. buying new books to languish).
What Springer did absolutely right is that she didn't make Enola into a little Sherlock clone. Sure she's bright and clever, but not really exceptionally so. Instead her defining characteristics are curiosity, creativity and determination. I *really* appreciate that! Also, the plot line is surprising. I expected that Enola would team up with her brother to solve a great mystery. It doesn't go down like that at all.
It could be called a weakness that the actual mystery in this story is rather slight and secondary, but I don't quite see it that way. I like that we really got to know Enola. Perhaps the future mysteries will be meatier and perhaps they won't. I don't' think it really matters as long as Enola is there to guide the way.
I must say that I'm glad I didn't foist this off on my nine year old daughter. She isn't ready for it - not necessarily for the content which (with a few small exceptions) is pretty tame, but for the literary context and historical setting which would fly right over her little head. That said, for older kids/tweens who have dabbled in Victorian literature (particularly if they've actually read a real Holmes story or two) this is a great fit!