This is the second book on the Lock and Key series, a fascinating imagining of how Sherlock Homes and James Moriarty first met - and how they ended up such mortal enemies. Not just that, but a tale of how two young boys grew up to become the great detective and the criminal mastermind to begin with.
In addition to the two obvious main characters, we have Moira, James Moriarty's sister. She narrates a great deal of the story, and is every bit as intelligent and involved as the two young men, however much they try to shield her or keep her uninvolved. It's not just sexism or the innate sense of superiority both boys have: females in the Moriarty family inevitable come to bad ends. Particularly clever ones. It makes the reader a bit unsure as to how things are going to turn out - especially as Sir Arthur Conan Doyle never mentioned Holmes being involved with any women...
The series occurs in modern times, and in the US, complete with cell phones and computers; but the boarding school atmosphere brilliantly lends an overall feeling of still being in Sir Arthur Conan Doyle's time period.
At the end of the first book I was definitely intrigued, and ordered the second before the publisher had a chance to send me a review copy (which they still did - score!). I had pretty much written James off as being beyond redemption at that point, but I underestimated Ridley's ability to create and maintain many-faceted characters. I mean, I know in one part of my brain that Moriarty isn't suddenly going to turn into the Pope, but the reader in me is still holding out hope, even after finishing book two!
Younger readers do not need to be familiar with the original tales to thoroughly enjoy these, but will probably want to explore those while waiting for book three. These would be an excellent choice for a book discussion group, with plenty of opportunity to share theories and sift out clues from red herrings. With that, here is one of my theories, with a good-sized spoiler, so - reader beware!
Lois is obviously trained as more than an assistant/nanny, as Moira has deduced. I think she has some sort of connection with the person they have decided is responsible for the Moriartys' father's death. Once you get to that part, you will understand the possible connection - although I do not think she is actually working for him. I also have some interesting theories about the love vs. loyalty angle, but that would give too many spoilers!