Ahh, Case Closed. Detective stories and hilariously bad sci-fi all in one. :)
This book covers two stories - first, a series of murders on a ship and second, the case of a doctor receiving strange mail from an unknown source, containing toys and money, along with a morning glory once a year. The first story is okay - solid and fast-paced but with nothing particularly memorable. But the second... oh the second.
Not only was the cause of the mail and the conclusion of this story pretty startling and a bit... sad? Not exactly the right word, but close. But in this book, we also get the first instance of Rachel (Jimmy/Conan's girlfriend from when he was normal, and who he is living with) starting to suspect that as illogical as it sounds, maybe that brainiac brat who's staying with them might actually be Jimmy.
It would have been easy for them to have never brought the idea up to her, but they did by the third book, which I really appreciate. Rachel's a clever, smart and resourceful lady. It would have felt like a betrayal of her character to never have her question the suspicious timing and the similarities between them. Conan's solution is clever even as it's obvious. (And the one slight issue with it made me laugh, though I suspect it was way more obvious in Japanese than in English)