Two mysteries for the price of one, this well written module requires a little more work from the Referee (Game Master) because of its deliberate open-ended sandbox setup. There is a mini-adventure followed by the larger mystery, so it lets your players become more invested in both the setting and the Noire flavored NPCs.
Even if you don't get to run the module, the complex and compelling NPCs are worth the price alone. They can be used for your own homebrewed adventures. I'm using it in my campaign and it fits perfectly.