Review:
This OVA is based on Black Butler manga volumes 9 through 11. I read them way back in 2013, so I could be wrong, but I'm pretty sure the OVA was very faithful to the manga.
I highly recommend that Black Butler newbies not start with this OVA. At the very least, watch Black Butler: Book of Circus first, since Book of Murder references it and parts of the story depend heavily upon it.
Okay, in Book of Murder Ciel is confronted by the "Double Charles." The Queen suspects Ciel lied about the circumstances behind all the deaths at the Baron's home back in Book of Circus, and she's giving him an opportunity to reaffirm his loyalty. He has been instructed to hold a party. She has selected the guest of honor, Georg von Siemens, to be accompanied by her butler, Charles Grey, and has allowed Ciel to choose the rest of his guests on his own.
The party seems to be a relatively ordinary affair, up until Georg is found stabbed to death in his room. After that, several other guests die. Only one guest could not possibly have committed the murder: Arthur, a struggling young writer who has so far only published one book, a detective novel. Arthur is asked to investigate the deaths and determine who the culprit is.
