Quick, fun little locked room mystery which only stays a locked room mystery for three and a half seconds, because Holmes solves it that fast. It takes him rather longer to get the rest of the mystery unraveled to his satisfaction, but even that is over quickly. (This may be more novella than novel length.)

The most interesting subplot, after the locked room bit, was the romance between Dr. Watson and Mary. It was both touching and entirely incredible, in that I find it hard to credit that poor, plodding old Watson falls head over heels at first glance. I suppose stranger things have happened, but even so, that was the quickest meet-cute-to-marriage-proposal I think I've ever read. I don't even mean in page count... did they know each other three days, or spend upwards of six hours in each other's company first? I doubt it, and I can't help but think that the greatest attraction, for Watson, is the prospect of living with someone other than Holmes. He's a fascinating man, of course, but there's a limit to how much cocaine and smugness one should have to stand before breakfast.